130604517 Cisco Press Metro Ethernet

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Copyright

The definitive guide to Enterprise and Carrier Metro Ethernet applications. About the Author
About the Technical Reviewers Acknowledgments Discover the latest Introduction

Icons in can This Book whatUsed they do for

developments in metro networking, Ethernet, and MPLS services and your organization

Learn the easy-to-read format that enables networking professionals of all levels to Goalsfrom and Methods understand the concepts Who Should Read This Book? Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Part I: Ethernet: From the LAN to Routing the MAN Architectures Halabi, author of Internet
Chapter 1. Introduction to Data in the Metro How This Book Is Organized

Metro networks will emerge as the next area of growth for the networking industry and will The Metro Network representEthernet a major shift in how data services are offered to businesses and residential customers. in the Metro The metro has always been challenging environment for delivering data services because it has The Early Metro Etherneta Movers been built to handle the stringent reliability and availability needs for voice. Carriers will have to The U.S. Incumbent Landscape go through fundamental shifts to equip the metro for next-generation data services demanded The International Landscape by enterprise customers and consumers. This is not only a technology shift, but also a shift in the A Data View of the Metro operational and business model that will allow the incumbent carriers to transform the metro to Metro Services offer enhanced data services.
Ethernet Access and Frame Relay Comparison

Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Conclusion view. It Chapter describes the Technologies current metro, which is based on TDM technology, and discusses the 2. Metro drivers and challenges carriers will face in transforming the metro to address data services.
Ethernet over SONET/SDH Resilient Packet Ring the adoption of metro Ethernet services and how that has led carriers Metro Ethernet discusses Ethernet Transport to the delivery of metro data services. With a changing mix of transport technologies, the book Conclusion then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual local area networks (VLAN), virtual private LAN services (VPLS), traffic Chapter private 3. Metro Ethernet Services engineering, and MPLS and Generalized MPLS (GMPLS). L2 Switching Basics Metro Ethernet Services Concepts Example of an L2 Metro Ethernet Service Challenges with All-Ethernet Metro Networks Conclusion

Chapter 4. Hybrid L2 and L3 IP/MPLS Networks Understanding VPN Components Delivering L3VPNs over IP L2 Ethernet Services over an IP/MPLS Network Conclusion Part II: MPLS: Controlling Traffic over Your Optical Metro Chapter 5. MPLS Traffic Engineering

• •

Advantages of Traffic Engineering

Table of Contents Index

Pre-MPLS Traffic Engineering Techniques Metro Ethernet MPLS and Traffic Engineering BySam Halabi Conclusion Chapter 6. RSVP for Traffic Engineering and Fast Reroute Publisher: Cisco Press Understanding RSVP-TE Pub Date: October 01, 2003 Understanding MPLS Fast Reroute ISBN: 1-58705-096-X Conclusion Pages: 240 Chapter 7. MPLS Controlling Optical Switches Understanding GMPLS Establishing the Need for GMPLS Signaling Models

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
Conclusion Chapter 8. GMPLS Architecture

Label Switching in a Nonpacket World

Discover latest developments in metro networking, Ethernet, and MPLS services and GMPLSthe Interfaces what they can do for your organization Modification of Routing and Signaling Learn from the easy-to-read format that enables networking professionals of all levels to Link Management Protocol understand the concepts
GMPLS Protection and Restoration Mechanisms Inclusion of Technology-Specific Parameters

GainSummary from the experience of industry and best-selling Cisco Press author, Sam of Differences Between MPLS and innovator GMPLS Halabi, author of Internet Routing Architectures Conclusion Metro networks will emerge as the next area of growth for the networking industry and will SONET/SDH Frame Formats represent a major shift in how data services are offered to businesses and residential customers. SONET/SDH Architecture The metro has always been a challenging environment for delivering data services because it has SONET/SDH Concatenation been built to handle the stringent reliability and availability needs for voice. Carriers will have to Conclusion go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise Glossary customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to A offer enhanced data services. B Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. ItDdescribes the current metro, which is based on TDM technology, and discusses the drivers E and challenges carriers will face in transforming the metro to address data services.
F C Appendix A. SONET/SDH Basic Framing and Concatenation

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers G to the delivery of metro data services. With a changing mix of transport technologies, the book I then examines current and emerging trends, and delves into the role of virtual private networks L (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic M engineering, and MPLS and Generalized MPLS (GMPLS).
N O P Q R

S T U V W Index

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Copyright
Copyright© 2003 Cisco Systems Published by: • Table of Contents Cisco Press • Index 800 East 96th Street, 3rd Floor Metro Ethernet Indianapolis, IN 46240 USA
BySam Halabi

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information Publisher: Cisco Press storage and retrieval system, without written permission from the publisher, except for the Pub Date: October 01, 2003 inclusion of brief quotations in a review. ISBN: 1-58705-096-X
Pages: 240 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0

Library of Congress Cataloging-in-Publication Number: 2002103527 First Printing September 2003 The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Warning and Disclaimer
Discover the latest developments in metro networking, Ethernet, and MPLS services and what is they can doto for your organization This book designed provide information about Metro Ethernet. Every effort has been made to make this book as complete and as accurate as possible, but no warranty or fitness is implied. Learn from the easy-to-read format that enables networking professionals of all levels to understandis the concepts The information provided on an "as is" basis. The author, Cisco Press, and Cisco Systems, Inc., shall have neither liability nor responsibility to any person or entity with respect to any loss Gain from the experience of industry innovatorin and best-selling Cisco author, Sam or damages arising from the information contained this book or from thePress use of the discs or Halabi, author of Internet Routing Architectures programs that may accompany it. Metro networks will emerge as book the next area of growth for theare networking industry and of will The opinions expressed in this belong to the author and not necessarily those Cisco represent a major shift in how data services are offered to businesses and residential customers. Systems, Inc. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to All terms mentioned in this book that are known to be trademarks or service marks have been offer enhanced data services. appropriately capitalized. Cisco Press or Cisco Systems, Inc. cannot attest to the accuracy of this information. Use of aCisco term Press in this bookat should not be regarded as affecting the validity any Metro Ethernet from looks the deployment of metro data services from a of holistic trademark or service mark. view. It describes the current metro, which is based on TDM technology, and discusses the

Trademark Acknowledgments

drivers and challenges carriers will face in transforming the metro to address data services.

Feedback Information Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers
to the delivery of metro data services. With a changing mix of transport technologies, the book then examines and emerging trends, technical and delves into of the role of virtual private At Cisco Press, current our goal is to create in-depth books the highest quality and networks value. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic the Each book is crafted with care and precision, undergoing rigorous development that involves engineering, and of MPLS and Generalized MPLS (GMPLS). unique expertise members from the professional technical community. Readers' feedback is a natural continuation of this process. If you have any comments regarding how we could improve the quality of this book, or otherwise alter it to better suit your needs, you can contact us through e-mail at [email protected]. Please make sure to include the book title and ISBN in your message.

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• Table of Contents

John Wait John Kane Anthony Wolfenden Sonia Torres Chavez Scott Miller Edie Quiroz Patrick Kanouse Dayna Isley Bill McManus Mike Bernico, Mark Gallo, Giles Heron, Irwin Lazar

Manager •Cisco Press Program Index
Metro Ethernet Manager, Marketing By Systems Sam Halabi

Communications, Cisco

Cisco Marketing Program Manager
Publisher: Cisco Press

Production Manager Pub Date: October 01, 2003 Development Editor
Pages: 240 ISBN: 1-58705-096-X

Copy Editor Technical Editors

Team Coordinator Tammi Ross The definitive guide to Enterprise and Carrier Metro Ethernet applications. Cover Designer Louisa Adair Discover the latest developments in metro networking, Ethernet, and MPLS services and Composition Interactive Composition Corporation what they can do for your organization Proofreader Gayle Johnson Learn from the easy-to-read format that enables networking professionals of all levels to Indexer Larry Sweazy understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Corporate Headquarters The metro has always been a challenging environment for delivering data services because it has Cisco Systems, Inc. the stringent reliability and availability needs for voice. Carriers will have to been built to handle 170 West Tasman Drive shifts to equip the metro for next-generation data services demanded go through fundamental San Jose, CA 95134-1706 by enterprise customers and consumers. This is not only a technology shift, but also a shift in the USA operational and business model that will allow the incumbent carriers to transform the metro to www.cisco.com offer enhanced data services. Tel: 408 526-4000 800 553-NETS (6387) Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Fax: 408 526-4100 view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. European Headquarters Cisco Metro Systems Ethernet International discusses theBV adoption of metro Ethernet services and how that has led carriers Haarlerbergpark to the delivery of metro data services. With a changing mix of transport technologies, the book Haarlerbergweg 13-19 and emerging trends, and delves into the role of virtual private networks then examines current 1101 CH Amsterdam (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic The Netherlands engineering, and MPLS and Generalized MPLS (GMPLS). www-europe.cisco.com Tel: 31 0 20 357 1000 Fax: 31 0 20 357 1100 Americas Headquarters

Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 USA www.cisco.com Tel: 408 526-7660 Fax:408 527-0883
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Asia Pacific Headquarters • Index Cisco Systems, Inc. Metro Ethernet Capital Tower By Sam Halabi 168 Robinson Road #22-01 to #29-01 Singapore Publisher:068912 Cisco Press www.cisco.com Pub Date: October 01, 2003 Tel: +65 6317 7777 ISBN: 1-58705-096-X Fax: +65 6317 7799
Pages: 240

Table of Contents

Cisco Systems has more than 200 offices in the following countries and regions. Addresses, phone numbers, and fax numbers are listed on the Cisco.com Web site at www.cisco.com/go/offices. Argentina • Australia • Enterprise Austria • Belgium • Brazil • Bulgaria Canada • Chile • China PRC • The definitive guide to and Carrier Metro Ethernet•applications. Colombia • Costa Rica • Croatia • Czech Republic • Denmark • Dubai, UAE • Finland • France • Germany • Greece • Hong Kong SAR • Hungary • India • Indonesia • Ireland • Israel • Italy • Discover latest developments in•metro networking, Ethernet, and MPLS services and • Japan • Korea the • Luxembourg • Malaysia Mexico • The Netherlands • New Zealand • Norway what they can do for your organization Peru • Philippines • Poland • Portugal • Puerto Rico • Romania • Russia • Saudi Arabia • Scotland • Singapore • Slovakia • Slovenia • South Africa • Spain • Sweden • Switzerland • Learn from the easy-to-read format that enables networking professionals of all•levels to • Taiwan • Thailand • Turkey • Ukraine • United Kingdom • United States • Venezuela Vietnam understand the concepts Zimbabwe Gain © from the experience of industry innovator and best-selling Cisco Samthe Copyright 2003 Cisco Systems, Inc. All rights reserved. CCIP, CCSP, the Press Cisco author, Arrow logo, Halabi, author of Internet Routing Architectures CiscoPowered Network mark, the Cisco Systems Verified logo, Cisco Unity, Follow Me Browsing, FormShare, iQ Net Readiness Scorecard, Networking Academy, and ScriptShare are trademarks Metro networks will emerge as the next area of growth for Play, the networking and Way will to of Cisco Systems, Inc.; Changing the Way We Work, Live, and Learn,industry The Fastest represent a major shift in how data services are offered to businesses and residential customers. Increase Your Internet Quotient, and iQuick Study are service marks of Cisco Systems, Inc.; and The metro has always been a challenging environment for CCNP, delivering data services because it has Aironet, ASIST, BPX, Catalyst, CCDA, CCDP, CCIE, CCNA, Cisco, the Cisco Certified been built to handle the stringent reliability and availability needs for voice. Carriers have to Internetwork Expert logo, Cisco IOS, the Cisco IOS logo, Cisco Press, Cisco Systems, will Cisco go through fundamental shifts to equip the metro for next-generation data services demanded Systems Capital, the Cisco Systems logo, Empowering the Internet Generation, by enterprise customers and consumers. This is not Step, only a technology shift, but also a shift in the Enterprise/Solver, EtherChannel, EtherSwitch, Fast GigaStack, Internet Quotient, IOS, operational and business model that will allow the incumbent carriers to transform the metro to IP/TV, iQ Expertise, the iQ logo, LightStream, MGX, MICA, the Networkers logo, Network offer enhanced data services. Registrar,Packet, PIX, Post-Routing, Pre-Routing, RateMUX, Registrar, SlideCast, SMARTnet, StrataView Plus, Stratm, SwitchProbe, TeleRouter, TransPath, and VCO are registered Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and certain other countries. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will facedocument in transforming the metro to address services. All other trademarks mentioned in this or Web site are the propertydata of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers and any other company. (0303R) to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks Printed in the USA (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Dedications
I dedicate this book to my wonderful family, who spent many nights and weekends alone to help me finish the manuscript. To my lovely wife, Roula, I promised you after the IRA book that I

wouldn't write another book. Sorry I lied. Thank you for supporting me. To my sons, Joe and Jason, I love you both for the sacrifices you had to make during the last year for me to finish this book.

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

About the Author
Mr. Halabi is a seasoned executive and an industry veteran with more than 18 years of experience marketing and selling to the worldwide Enterprise and Carrier networking markets. While at Cisco, heof wrote the first Cisco Internet routing book, Internet Routing Architectures, a • Table Contents best-seller in the U.S. and international markets. He has held multiple executive management • Index positions in the field of marketing, sales, and business development and has been instrumental Metro Ethernet in evolving fast-growing businesses for the Enterprise and Carrier Ethernet markets.
BySam Halabi

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

About the Technical Reviewers
Mike Bernico is a senior networking engineer at the Illinois Century Network. In this position, he focuses primarily on network design and integrating advanced network services such as QoS, IP Multicast, IPv6, and MPLS into the network. He has also authored open-source software • Table of Contents related to his interests in new networking technologies. He enjoys reading and spending time in • Index the lab increasing his knowledge of the networking industry. He lives in Illinois with his wife Metro Ethernet Jayme. He can be contacted at [email protected].
BySam Halabi

Mark Gallo is a technical manager with America Online. His network certifications include Cisco CCNP and Cisco CCDP. He has led several engineering groups responsible for designing and Publisher: Cisco Press implementing enterprise LANs and international IP networks. He has a BS in electrical Pub Date: October 01, 2003 engineering from the University of Pittsburgh. He resides in northern Virginia with his wife, 1-58705-096-X Betsy, ISBN: and son, Paul.
Pages: 240

Giles Heron is the principal network architect for PacketExchange, a next-generation carrier providing Ethernet services on a global basis. He designed PacketExchange's MPLS network and has been instrumental in the development of its service portfolio. A cofounder of PacketExchange, he previously worked in the Network Architecture group at Level(3) Communications. Heto isEnterprise coauthor of the draft-martini specification for transport of Layer 2 The definitive guide and Carrier Metro Ethernet applications. protocols over IP and MPLS networks and the draft-lasserre-vkompella specification for emulation of multipoint Ethernet LAN segments over MPLS, as well as various other Internet drafts. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Irwin Lazar is practice manager for Burton Group in its Networks and Telecom group, managing team of consultants who advise large end-user organizations on topics including Learnafrom the easy-to-read format that enables networking professionals of all levels to network architecture and emerging network technologies. He administers The MPLS Resource understand the concepts Center (http://www.mplsrc.com) and is the conference director for the MPLScon Conference and Exhibition. Gain from He has the published experience numerous of industry articles innovator on topics and relating best-selling to data Cisco networking Press author, and Sam the Internet Halabi, and author is a frequent of Internet speaker Routing on networking-related Architectures topics at many industry conferences. He holds a bachelor's degree in management information systems from Radford University and Metro networks will emerge the next He area growth for the networkingSystems industrySecurity and will an MBA from George Mason as University. is of also a Certified Information represent a major shift in how data services are offered to businesses and residential customers. Professional (CISSP). The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Acknowledgments
I would like to acknowledge many individuals who made this book possible. Many thanks to Giles Heron from PacketExchange for his thorough review of the material and to his many contributions to the Metro Ethernet space. I would like to thank Irwin Lazar, Mike Bernico, Mark • Table of Contents Gallo, and Saaed Sardar for their contributions and for keeping me honest. Thanks to Andrew • Index Malis for his initial work on this project. I also would like to thank many of the authors of the Metro Ethernet IETF RFCs and IETF drafts whose information has been used for some of the concepts and BySam Halabi definitions in this book. This includes the following people: Luca Martini, Nasser El-Aawar, Eric Rosen, and Giles Heron for their work on the encapsulation of Ethernet frames over IP/MPLS Publisher: Cisco Press networks. V. Kompella, Mark Lasserre, Nick Tingle, Sunil Khandekar, Ali Sajassi, Tom Soon, Yetik Pub Serbest, Date: October Eric01, Puetz, 2003 Vasile Radaoca, Rob Nath, Andrew Smith, Juha Heinanen, Nick Slabakov, J. Achirica, L. Andersson, Giles Heron, S. Khandekar, P. Lin, P. Menezes, A. ISBN: 1-58705-096-X Moranganti, H. Pages: 240 Ould-Brahim, and S. Yeong-il for their work on the VPLS draft specification. K. Kompella for his original work on the DTLS draft specification. Special thanks to Daniel O. Awduche for his many contributions to traffic engineering requirements and his phenomenal work in driving multiprotocol lambda switching and GMPLS. Thanks to J. Malcolm, J. Agogbua, M. O'Dell, and J. McManus for their contributions to TE requirements. Many thanks to the CCAMP group and its many contributors to GMPLS, including Peter Ashwood Smith, Eric Mannie, Thomas The definitive guide to Enterprise and Carrier Metro Ethernet applications. D. Nadeau, Ayan Banerjee, Lyndon Ong, Debashis Basak, Dimitri Papadimitriou, Lou Berger, Dimitrios Pendarakis, Greg Bernstein, Bala Rajagopalan, Sudheer Dharanikota, Yakov Rekhter, John Discover Drake, Debanjan Saha, Yanhe Fan, Sandick, Don Fedyk, Vishal Sharma, Gert Grammel, the latest developments in Hal metro networking, Ethernet, and MPLS services and George Swallow, Dan Guo, Kireeti Kompella, Jennifer Yates, Alan Kullberg, George R. Young, what they can do for your organization Jonathan P. Lang, John Yu, Fong Liaw, and Alex Zinin. I would also like to thank the Metro Ethernet Forum MPLS Forum for many of their networking informativeprofessionals references about and Learn fromand the the easy-to-read format that enables of allMPLS levels to VPLS. I am sure I have missed many of the names of talented people who contributed indirectly understand the concepts to the concepts in this book, many thanks for your efforts. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Last but not least, many thanksRouting to Cisco Systems and the Cisco Press team, John Kane, Dayna Halabi, author of Internet Architectures Isley, and others for supporting this project. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Icons Used in This Book
Throughout this book, you see the following icons:
• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Introduction
Metro Ethernet—opposites attract. Ethernet is a technology that has had major success in the LAN, displacing other once-promising technologies such as Token Ring, FDDI, and ATM. Ethernet's simplicity and price/performance advantages have made it the ultimate winner, • Table of Contents extending from the enterprise workgroup closet all the way to the enterprise backbone and data • Index centers. The metro is the last portion of the network standing between subscribers or businesses Metro Ethernet and the vast amount of information that is available on the Internet. The metro is entrenched BySam Halabi with legacy time-division multiplexing (TDM) and SONET/SDH technology that is designed for traditional voice and leased-line services. These legacy technologies are inadequate for handling Cisco Press the Publisher: bandwidth demands of emerging data applications.
Pub Date: October 01, 2003

Ethernet in 1-58705-096-X the metro can be deployed as an access interface to replace traditional T1/E1 TDM ISBN: interfaces. Many data services are being deployed in the metro, including point-to-point Ethernet Pages: 240 Line Services and multipoint-to-multipoint Ethernet LAN services or Virtual Private LAN services (VPLS) that extend the enterprise campus across geographically dispersed backbones. Ethernet can run over many metro transport technologies, including SONET/SDH, next-generation SONET/SDH, Resilient Packet Ring (RPR), and wavelength-division multiplexing (WDM), as well as over pure Ethernet transport. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Ethernet, however, was not designed for metro applications and lacks the scalability and reliability required for mass deployments. Deploying Ethernet in the metro requires the Discover latest developments metro networking, Ethernet, and MPLS services and scalability and the robustness features thatin exist only in IP and Multiprotocol Label Switching (MPLS) what they can do for your organization control planes. As such, hybrid Layer 2 (L2) and Layer 3 (L3) IP and MPLS networks have emerged as a solution that marries Ethernet's simplicity and cost effectiveness with the scale of Learn from the easy-to-read format that enables networking professionals of all levels to IP and MPLS networks. With many transport technologies deployed in the metro, Ethernet understand the concepts services have to be provisioned and monitored over a mix of data switches and optical switches. It becomes essential to find a control plane that can span both data and optical networks. MPLS Gain from the experience of industry innovator and best-selling Cisco Press author, Sam has been extended to do this task via the use of the Generalized MPLS (GMPLS) control plane, Halabi, author of Internet Routing Architectures which controls both data and optical switches. Understanding these topics and more will help you master the metro space as and itsnext many intricacies. Metro networks will emerge the area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Goals and Methods
The goal of this book is to make you familiar with the topic of metro Ethernet—what it is, how it started, and how it has evolved. One thing is for certain: after you read this book, you will never be intimidated by the metro Ethernet topic again. You will be familiar with the different • Table ofas Contents technologies, such Ethernet switching, RPR, next-generation SONET/SDH, MPLS, and so on, in • Index the context of metro deployments.
Metro Ethernet

The industry BySam Halabi today is divided among different pools of expertise—LAN switching, IP routing, and transport. These are three different worlds that require their own special knowledge base. LAN switching expertise is specific to individuals who come from the enterprise space, IP routing Publisher: Cisco Press expertise is more specific to individuals who deal with public and private IP routed backbones, Date: October 01, 2003 andPub transport expertise is specific to individuals who deal with TDM and optical networks. The ISBN: 1-58705-096-X metro blends all these areas of expertise. This book attempts to bridge the gap between Pages:LAN, 240 IP/MPLS, and transport knowledge in the same way metro bridges the gap enterprise between enterprise networks and IP routed backbones over a blend of transport technologies. The style of this book is narrative. It goes from simple to more challenging within each chapter and across chapters. The big picture is always presented first to give you a better view of what is being described in the and then the text goes into more details. It is possible to skip the The definitive guide to chapter, Enterprise and Carrier Metro Ethernet applications. more detailed sections of the book and still have a complete picture of the topic. I call the different levels within a chapter or across chapters "warps." Different readers will find comfort in different warps. The main thing is to learn something new and challenging time youand enter Discover the latest developments in metro networking, Ethernet, and every MPLS services a new warp. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Who Should Read This Book?
The book is targeted at a wide audience, ranging from nontechnical, business-oriented individuals to very technical individuals. The different people who have interest in the subject include network operators, engineers, consultants, managers, CEOs, and venture capitalists. • Table of Contents Enterprise directors of technology and CIOs will read the book to assess how they can build • Index scalable virtual enterprise networks. Telecom operators will find in the book a way to move into Metro Ethernet selling next-generation data services. Engineers will augment their knowledge base in the areas ofSam Ethernet By Halabi switching, IP/MPLS, and optical networks. Salespeople will gain expertise in selling in a fast-growing metro Ethernet market. Last but not least, businesspeople will understand the topic to the level where they can make wise investments in the metro Ethernet space. Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

How This Book Is Organized
This book is organized into two main parts: Part I—Ethernet: Table of Contents From the LAN to the MAN
Index

• •

part Metro This Ethernet

of the book—Chapters 1 through 4—starts by describing the different drivers that motivated the adoption of metro Ethernet services and how they have evolved in the United BySam Halabi States versus internationally. You will see how Ethernet has moved from the LAN into the MAN and how it is complementing existing and emerging metro technologies such as Publisher: Cisco Press SONET/SDH, next-generation SONET, RPR, and WDM. You will then learn about the Pub Date: October 01, 2003 different Ethernet services, such as point-to-point Ethernet Line Services and multipoint-tomultipoint ISBN: 1-58705-096-X Ethernet LAN services as represented by the concept of Virtual Private LAN Service (VPLS). This part of the book explains the challenges of deploying Ethernet Pages: 240 networks and how hybrid Ethernet and IP MPLS networks have emerged as a scalable solution for deploying L2 Ethernet VPN services. Part II—MPLS Controlling Traffic over Your Optical Metro The definitive guide to Enterprise and Carrier Metro Ethernet applications. MPLS is an important technology for scaling metro deployments. Whereas the first part of the book discusses MPLS in the context of building Layer 2 metro Ethernet VPNs, Part II—Chapters 5 through 8—explores the use of MPLS to control the traffic trajectory in the Discover the latest developments in metro networking, Ethernet, and MPLS services and optical metro. The metro is built with data-switching, SONET/SDH, and optical-switching what they can do for your organization systems. The act of provisioning different systems and controlling traffic across packet and optical systems is difficult and consitutes a major networking operationalprofessionals expense. GMPLS has Learn from the easy-to-read format that enables of all levels to extended the use of MPLS as a universal control plane for both packet/cell and optical understand the concepts systems. GMPLS is one of those "warp 7" subjects. Part II first familiarizes you with the subject of traffic engineering and how the RSVP-TE protocol is used to control Gain from the experience of industry innovator and signaling best-selling Cisco Press author, Sam traffic trajectory reroute traffic in the case of failure. This makes the transition into the Halabi, author ofand Internet Routing Architectures topic of GMPLS go smoother, with many of the basic traffic engineering in packet/cell networks already defined. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Chapters 1has through 8 and the appendix cover the following topics: data services because it has The metro always been a challenging environment for delivering been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Chapter 1, "Introduction to Data in the Metro"— The metro has always been a by enterprise customers and consumers. This is not only a technology shift, but also a shift in the challenging environment for delivering data services, because it was built to handle the operational and business model that will allow the incumbent carriers to transform the metro to stringent reliability and availability needs of voice communications. The metro is evolving offer enhanced data services. differently in different regions of the world, depending on many factors. For example, Ethernet is evolving in the the deployment U.S. because legacy TDM deployments stiff Metrometro Ethernet from Cisco Press slowly looks at ofof metro data services from a and holistic regulations, but it is evolving quickly in other parts of the world, especially in Asia and view. It describes the current metro, which is based on TDM technology, and discusses the Japan, which do not have will as many legacy TDM deployments are not data as heavily drivers and challenges carriers face in transforming the metro and to address services. regulated. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Chapter Technologies"— Ethernet do not necessitatethe an book allto the delivery 2, of "Metro metro data services. With Metro a changing mix services of transport technologies, Ethernet Layer 2 network; rather, they can be deployed over different technologies such as then examines current and emerging trends, and delves into the role of virtual private networks next-generation SONET/SDH and IP/MPLS networks. This chapter goes into more details (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic about the different technologies used in the metro. engineering, and MPLS and Generalized MPLS (GMPLS). Chapter 3, "Metro Ethernet Services"— Ethernet over SONET, Resilient Packet Ring, and Ethernet transport are all viable methods to deploy a metro Ethernet service. However, functionality needs to be offered on top of metro equipment to deliver revenue-generating services such as Internet connectivity or VPN services. Chapter 3 starts by discussing the basics of Layer 2 Ethernet switching to familiarize you with Ethernet switching concepts.

You'll then learn about the different metro Ethernet services concepts as introduced by the Metro Ethernet Forum (MEF). Defining the right traffic and performance parameters, class of service, and service frame delivery ensures that buyers and users of the service understand what they are paying for and also helps service providers communicate their capabilities. Chapter 4, "Hybrid L2 and L3 IP/MPLS Networks"— Chapter 4 focuses first on describing a pure Layer 3 VPN implementation and its applicability to metro Ethernet. This • Table of Contents gives you enough information to compare Layer 3 VPNs and Layer 2 VPNs relative to metro • Index Ethernet applications. The chapter then delves into the topic of deploying L2 Ethernet Metro Ethernet services over a hybrid L2 Ethernet and an L3 IP/MPLS network. Some of the basic BySamscalability Halabi issues that are considered include restrictions on the number of customers because of the VLAN-ID limitations, scaling the Layer 2 backbone with spanning tree, service provisioning and monitoring, and carrying VLAN information within the network. Publisher: Cisco Press
Pub Date: October 01, 2003

Chapter 5, "MPLS Traffic Engineering"— Previous chapters discussed how metro ISBN: 1-58705-096-X Ethernet Layer 2 services can be deployed over an MPLS network. Those chapters also Pages: 240 covered the concept of pseudowires and LSP tunnels. In Chapter 5, you'll learn about the different parameters used for traffic engineering. Traffic engineering is an important MPLS function that allows the network operator to have more control over how traffic traverses its network. This chapter details the concept of traffic engineering and its use.

Chapter guide 6, "RSVP for Traffic Engineering and Fast Reroute"— MPLS plays a big role The definitive to Enterprise and Carrier Metro Ethernet applications. in delivering and scaling services in the metro, so you need to understand how it can be used to achieve traffic engineering and protection via the use of Resource Reservation Discover the latest developments in metro networking, and MPLS through services the anduse Protocol traffic engineering (RSVP-TE). In this chapter, Ethernet, you see how MPLS, what they can do for your organization of RSVP-TE, can be used to establish backup paths in the case of failure. This chapter discusses the basics of RSVP-TE and how it can be applied to establish LSPs, bandwidth Learn fromand the fast-reroute easy-to-read format thatYou'll enables professionals all levels to allocation, techniques. getnetworking a detailed explanation of of the RSVP-TE understand the concepts messages and objects to give you a better understanding of this complex protocol. Gain from the experience of industry innovator and best-selling Cisco upon Press which author, Sam Chapter 7, "MPLS Controlling Optical Switches"— The principles MPLS Halabi, author of Internet Routing Architectures technology is based are generic and applicable to multiple layers of the transport network. As such, MPLS-based control of other network layers, such as the TDM and optical layers, is Metro networks will Chapter emerge 7 as the next why areaGeneralized of growth for the networking and will also possible. discusses MPLS (GMPLS) is industry needed to represent a major shift in how data services are offered to businesses and residential customers. dynamically provision optical networks. You'll learn about the benefits and drawbacks of The metro has always been a challenging environment for delivering data services because both static centralized and dynamic decentralized provisioning models. Chapter 7 also it has been introduces built to handle stringent reliability and availability needs forand voice. Carriers will have you the to the different signaling models (overlay, peer, augmented) and to to go through fundamental shifts to equip the metro for next-generation data services demanded how GMPLS uses labels to cross-connect the circuits for TDM and WDM networks. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent to attempts transform the metro to Chapter 8, "GMPLS Architecture"— Generalized MPLScarriers (GMPLS) to address offer some enhanced data services. of the challenges that exist in optical networks by building on MPLS and extending its control parameters to handle the scalability and manageability aspects of optical networks. MetroThis Ethernet from Cisco Press looks at the deployment of architecture, metro data services a holistic chapter explains the characteristics of the GMPLS such asfrom the extensions view.to It routing describes the current metro, which is based on TDM technology, and discusses and signaling and the technology parameters that GMPLS adds to MPLSthe to be drivers and challenges carriers will face in transforming the metro to address data services. able to control optical networks. MetroAppendix, Ethernet discusses the adoption of metro Ethernet services and how that has led carriers "SONET/SDH Basic Framing and Concatenation"— This appendix presents to the delivery of metro data services. With a changing mix of transport technologies, the book the basics of SONET/SDH framing and how the SONET/SDH technology is being adapted via then examines and emerging trends, and delves into the role of virtual private networks the use of current standard and virtual concatenation to meet the challenging needs of emerging (VPN), virtual local area networks (VLAN), virtual private LAN (VPLS), traffic data overprivate SONET/SDH networks in the metro. The emergence of services L2 metro services will engineering, and MPLS and Generalized MPLS (GMPLS). challenge the legacy SONET/SDH network deployments and will drive the emergence of multiservice provisioning platforms that will efficiently transport Ethernet, Frame Relay, ATM, and other data services over SONET/SDH.

Part I: Ethernet: From the LAN to the MAN
Chapter 1 Introduction to Data in the Metro
• Table of Contents • Chapter 3 Metro Index Ethernet Services
Metro Ethernet BySam Halabi

Chapter 2 Metro Technologies

Chapter 4 Hybrid L2 and L3 IP/MPLS Networks

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 1. Introduction to Data in the Metro
• of Contents This chapter Table covers the following topics: •
Metro Ethernet BySam Halabi

Index

The Metro Network Ethernet in the Metro

Publisher: Cisco Press

The Early Metro Ethernet Pub Date: October 01, 2003
ISBN: 1-58705-096-X Pages: 240

Movers

The U.S. Incumbent Landscape The International Landscape A Data View of the Metro Metro Services The definitive guide to Enterprise and Carrier Metro Ethernet applications. Ethernet Access and Frame Relay Comparison Discover the latest developments in metro networking, Ethernet, and MPLS services and The metro, the first span the organization network that connects subscribers and businesses to the WAN, what they can do forof your has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs of voice communications. metroto is Learn from the easy-to-read format that enables networking professionals ofThe all levels evolving differently in different regions of the world depending on many factors, including the understand the concepts following: Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Type of service provider— Metro deployments vary with respect to the type of service providers building them. While regional Bell companies (RBOCs) are Metro networksthat will are emerge as the next area of growth for operating the networking industry and will inclined to build traditional SONET/SDH metro networks, greenfield operators have the represent a major shift in how data services are offered to businesses and residential customers. tendency buildbeen more rather than evolutionary networks. The metro has to always arevolutionary challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Geography— U.S. shifts deployments differ from deployments in Europe, Asia Pacific, Japan, and go through fundamental to equip the metro for next-generation data services demanded so on. For example, while many metro deployments in the U.S. are SONET centric, China by enterprise customers and consumers. This is not only a technology shift, but also a shift in the and Korea are not tied down to legacy deployments and therefore could adopt an Ethernet operational and business model that will allow the incumbent carriers to transform the metro to faster. offer network enhanced data services. Regulations tie toat geography and the type of service providers. Europe, for MetroRegulations— Ethernet from Cisco Press looks the deployment of metro data services from a holistic example, has less regulation than the U.S. as far as defining the boundary between a data view. It describes the current metro, which is based on TDM technology, and discusses the network and a Synchronous Digital Hierarchy (SDH) network; hence, the adoption of drivers and challenges carriers will face in transforming the metro to address data services. Ethernet over SDH deployments could move faster in Europe than in the U.S. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

The Metro Network
The metro is simply the first span of the network that connects subscribers and businesses to the WAN. The different entities serviced by the metro include residential and business customers, examples of which are large enterprises (LEs), small office/home office (SOHO), small and • Table of Contents medium-sized businesses (SMBs), multitenant units (MTUs), and multidwelling units (MDUs) • Index (seeFigure 1-1).
Metro Ethernet BySam Halabi

Figure 1-1. The Metro

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability for voice. Carriers the will last have to The portion of the metro that touches the customer is called needs the last mile to indicate go through fundamental shifts to equip the metro for next-generation data services demanded span of the carrier's network. In a world where the paying customer is at the center of the by enterprise customers and consumers. is not only technology shift, but customer also a shift in the universe, the industry also calls this spanThis the first mile toaacknowledge that the comes operational and business model that will allow the incumbent carriers to transform the metro to first. An adequate term would probably be "the final frontier" because the last span of the offer enhanced data services. network is normally the most challenging and the most expensive to build and is the final barrier for accelerating the transformation of the metro into a high-speed data-centric network. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based multiplexing on TDM technology, and discusses the is The legacy metro consists primarily of time-division (TDM) technology, which drivers and challenges carriers will face in transforming the metro to address data services. very optimized for delivering voice services. A typical metro network consists of TDM equipment placed in the basement of customer buildings and incumbent local exchange carrier (ILEC) Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers central offices. The TDM equipment consists of digital multiplexers, digital access cross-connects to the delivery of metro data services. With a changing mix of transport technologies, the book (DACs, often referred to as digital cross-connects), SONET/SDH add/drop multiplexers (ADMs), then examines current and emerging trends, and delves into the role of virtual private networks SONET/SDH cross-connects, and so on. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Figure 1-2 shows a TDM view of a legacy metro deployment. This scenario shows connectivity to business customers for on-net and off-net networks. An on-net network is a network in which fiber reaches the building and the carrier installs an ADM in the basement of the building and offers T1 or DS3/OCn circuits to different customers in the building. In this case, digital multiplexers such as M13s multiplex multiple T1s to a DS3 or multiple DS3s to an OCn circuit that is carried over the SONET/SDH fiber ring to the central office (CO). In an off-net network, in

which fiber does not reach the building, connectivity is done via copper T1 or DS3 circuits that are aggregated in the CO using DACS. The aggregated circuits are cross-connected in the CO to other core COs, where the circuits are terminated or transported across the WAN depending on the service that is being offered.

Figure 1-2. A TDM View of the Metro
• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. The operation and installation of a pure TDM network is very tedious and extremely expensive to deploy, because TDM itself is a very rigid and does not have the flexibility or the Discover the latest developments in technology metro networking, Ethernet, and MPLS services and economics to scale with the needs of the customer. The cost of deploying metro networks is the what they can do for your organization sum of capital expenditure on equipment and operational expenditure. Operational expenditure includes the cost the of network planning, installation, operation and management, maintenance Learn from easy-to-read format that enables networking professionals of all levels toand troubleshooting, and so on. What is important to realize is that these operational expenditures understand the concepts could reach about 70 percent of the carrier's total expenditure, which could weigh heavily on the carrier's Gain decision from the regarding experience which of industry products innovator and technologies and best-selling to installCisco in the Press network. author, Sam Halabi, author of Internet Routing Architectures The cost of bringing up service to a customer has a huge effect on the success of delivering that Metro networks service. The lesswill theemerge carrier has as the to touch next area the customer of growth premises for the networking and CO equipment industry and to deliver will represent initial and a incremental major shift service, in how data the higher services the are carrier's offered return to businesses on investment and residential will be for customers. that The metro The customer. has term always truck been rolls a challenging refers to the environment trucks that for aredelivering dispatched data to the services customer because premises it has been to activate built to or handle modifythe a particular stringent service. reliability The and more availability truck rolls needs required for voice. for aCarriers customer, will the have more to go through money the carrier fundamental is spending shifts on to equip that customer. the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the The challenge that TDM interfaces have that the incumbent bandwidth carriers they offer not grow operational and business model that willis allow todoes transform the linearly metro to with but rather grows in step functions. A T1 interface, for example, offers offer customer enhanceddemands data services. 1.5 Mbps; the next step function is a DS3 interface at 45 Mbps; the next step function is an OC3 Metro Ethernet interface at 155from Mbps; Cisco andPress so on. looks So when at the a deployment customer's bandwidth of metro data needs services exceed from the a 1.5-Mbps holistic view. the rate, It describes carrier is the forced current to offer metro, the which customer is based multiple on TDM T1 (nXT1) technology, circuits and or move discusses to a the DS3 driversand circuit andgive challenges the customer carriers a will portion faceof inthe transforming DS3. The end the metro effect is tothat address the physical data services. interface sold to the customer has changed, and the cost of the change has a major impact on both the Metro discusses the adoption of metro Ethernet services and how that has led carriers carrierEthernet and the customer. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines Moving from a T1 current interface and emerging to an nXT1 trends, or DS3/OCn and delves requires intochanges the role to of the virtual customer private premises networks (VPN), virtual equipment (CPE) private to support local area the networks new interface (VLAN), and virtual also requires privatechanges LAN services to the (VPLS), CO equipment traffic to engineering, and accommodate theMPLS new deployed and Generalized circuits.MPLS This will (GMPLS). occur every time a customer requests a bandwidth change for the life of the customer connection. Services such as Channelized DS1, Channelized DS3, and Channelized OCn can offer more flexibility in deploying increments of bandwidth. However, these services come at a much higher cost for the physical interface and routers and have limited granularity. This is one of the main drivers for the proliferation of Ethernet in the metro as an access interface. A 10/100/1000 Ethernet interface scales much

better from submegabit speeds all the way to gigabit, at a fraction of the cost of a TDM interface. Figure 1-3 shows the difference between the TDM model and Ethernet model for delivering Internet connectivity. In the TDM model, the metro carrier, such as an ILEC or RBOC, offers the point-to-point T1 circuit, while the ISP manages the delivery of Internet services, which includes managing the customer IP addresses and the router connectivity in the point of presence (POP). This normally has been the preferred model for ILECs who do not want to get involved in the IP addressing and in routing the IP traffic. In some cases, the ILECs can outsource the service or • Table of Contents manage the whole IP connection if they want to. However, this model keeps a demarcation line • Index between the delivery of IP services and the delivery of connectivity services.
Metro Ethernet BySam Halabi

Figure 1-3. Connectivity: TDM Versus Ethernet

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam In the Ethernet model, both network interfaces on the customer side and the ISP side are Halabi, author of Internet Routing Architectures Ethernet interfaces. The ILEC manages the Layer 2 (L2) connection, while the ISP manages the IP services. From anemerge operational perspective, this arrangement keeps the ILEC in a and model similar Metro networks will as the next area of growth for the networking industry will to the T1 private-line service; however, it opens up the opportunity for the ILEC to up-sell represent a major shift in how data services are offered to businesses and residential customers. additional on top of the same Ethernet connection any changes to the CPE and The metro service has always been a challenging environment for without delivering data services because it has the network. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Ethernet in the Metro
Ethernet technology has so far been widely accepted in enterprise deployments, and millions of Ethernet ports have already been deployed. The simplicity of this technology enables you to scale the Ethernet interface to high bandwidth while remaining cost effective. The cost of a 100• Table Contents workgroup L2 LAN switches will be less than $50 in the next few Mbps interface forof enterprise • Index years.
Metro Ethernet

These costs and performance metrics and Ethernet's ease of use are motivating carrier networks BySam Halabi to use Ethernet as an access technology. In this new model, the customer is given an Ethernet interface rather than a TDM interface.
Publisher: Cisco Press Date: October 2003 ThePub following is a 01, summary of the value proposition that an Ethernet access line offers relative to ISBN: 1-58705-096-X TDM private lines: Pages: 240

Bandwidth scalability— The low cost of an Ethernet access interface on both the CPE device and the carrier access equipment favors the installation of a higher-speed Ethernet interface that can last the life of the customer connection. Just compare the cost of having a single installation of a 100-Mbps Ethernet interface versus the installation of a T1 interface The definitive guide to Enterprise and Carrierservice, Metro Ethernet applications. for 1.5-Mbps service, a T3 for 45-Mbps and an OC3 (155 Mbps) for 100-Mbps service. A TDM interface offering results in many CPE interface changes, many truck rolls deployed to the customer premises, and equipment that only gets more expensive with Discover the latest developments in metro networking, Ethernet, and MPLS services andthe speed of the interface. what they can do for your organization Bandwidth granularity— An Ethernet be provisioned to deliver tiered Learn from the easy-to-read format thatinterface enables can networking professionals of all levels to bandwidth that scales to the maximum interface speed. By comparison, a rigid TDM understand the concepts hierarchy changes in big step functions. It is important to note that bandwidth granularity is notfrom a function specific to Ethernet rather is specific to any Cisco packet interface. Early Gain the experience of industrybut innovator and best-selling Press author, Sam deployments ofof metro Ethernet struggled with this function because many enterprise-class Halabi, author Internet Routing Architectures Ethernet switches did not have the capability to police the traffic and enforce SLAs. Metro networks will emerge as the next area of growth for the networking industry and will Fast a provisioning— Deploying an Ethernet service results in a different operational model represent major shift in how data services are offered to businesses and residential customers. in which packet leased lines are provisioned instead of TDM circuit leased lines. The packet The metro has always been a challenging environment for delivering data services because it has model can be done much faster than the legacy model because been provisioning built to handle the stringent reliability and availability needs TDM for voice. Carriers will have to provisioning can be done without changing network equipment and interfaces. Packet go through fundamental shifts to equip the metro for next-generation data services demanded provisioning is a simple function of changing software parameters that but would throttle by enterprise customers and consumers. This is not only a technology shift, also a shift the in the packets and can increase or decrease bandwidth, establish a connection in minutes, and to bill operational and business model that will allow the incumbent carriers to transform the metro for the new service. offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

The Early Metro Ethernet Movers
The earliest service providers to move into the metro Ethernet space appeared in the 1999–2000 timeframe in the midst of the telecom bubble and have adopted variations of the same business model across the world.
• Table of Contents • Index In the U.S., the early adopters of metro Ethernet were the greenfield service providers that Metro Ethernet wanted to provide services to some niche segments, such as SMBs that are underserved by the incumbent BySam Halabiproviders. Other providers have found an opportunity in promoting cheaper bandwidth by selling Ethernet pipes to large enterprises or to other providers such as ISPs or content providers.
Publisher: Cisco Press Date: October 01, 2003 consist of BLECs and metro operators, which are discussed next. ThePub greenfield operators ISBN: 1-58705-096-X Pages: 240

The BLECs
The Building Local Exchange Carriers (BLECs) have adopted a retail bandwidth model that offers services to SMBs which are concentrated in large MTUs. (These are the "tall and shiny buildings" The guide to Enterprise and Carrier Metrocity Ethernet applications. that definitive are usually located in concentrated downtown areas.) The BLECs focus on wiring the inside of the MTUs for broadband by delivering Ethernet connections to individual offices. The BLECs capitalize on the fact that from the time an SMB places an order, it takes an incumbent Discover the latest developments in metro networking, Ethernet, and MPLS services and operator three to six months to deploy a T1 circuit for that SMB. The BLECs can service the what they can do for your organization customers in weeks, days, or even hours rather than months and at much less cost. Learn from the easy-to-read format that enables networking professionals of all levels to As shown in Figure 1-4, a BLEC installs its equipment in the basement of the MTU, runs Ethernet understand the concepts in the risers of the building, and installs an Ethernet jack in the customer office. The customer can then get all the of its data services from the Ethernet connection. Gain from experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

Figure 1-4. The BLEC Network Model
Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

The Metro Ethernet Carrier
Although the BLECs are considered metro operators, they specialize in servicing the MTU customers rather than building connectivity within the metro itself. The metro carriers are focused on building connectivity within the metro and then selling connectivity to BLECs, large enterprises, or even other service providers, depending on the business model. However, a lot of consolidation has occurred because metro operators have acquired BLECs, blurring the • Table of Contents distinction between the two different providers.
• Index
Metro Ethernet Whereas some metro carriers have adopted a retail model, selling bandwidth to large enterprises, BySam Halabi other metro carriers have adopted a wholesale model, selling bandwidth to other service providers (see Figure 1-5). Publisher: Cisco Press

Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 1-5. Retail Versus Wholesale Model

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Architectures OtherHalabi, business plans for metro Routing deployments target cities that want to enhance the quality of life and attract business by tying the whole city with a fiber network that connects schools, Metro networks will emerge as the next area of growth for the networking industry and will universities, businesses, financial districts, and government agencies. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to The Greenfield Value Proposition go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model the that will allow the incumbent carriers to transform the metro to The following sections describe value proposition that greenfield operators can offer to offer enhanced services. attract businessdata away from the incumbents. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Bringing the Service Up in Days Rather Than Months drivers and challenges carriers will face in transforming the metro to address data services. As mentioned earlier, onethe of the key selling points for theservices metro greenfield operators is carriers their Metro Ethernet discusses adoption of metro Ethernet and how that has led ability to bring of service up in days. However, to accomplish the service has to be almost to the delivery metro data services. With a changing mixthis, of transport technologies, the book ready to be brought upand once the customer requests it. Greenfields spend a lot of money on idle then examines current emerging trends, and delves into the role of virtual private networks connections, waiting a customer to appear. (VPN), virtual privatefor local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Pay as You Grow Model
With an Ethernet connection, the customer can purchase an initial amount of bandwidth and SLA and then has the option to change the service in the future by simply calling the provider. The

provider could then immediately assign the customer to a different SLA by changing the network parameters via software. Some metro operators offer their customers the ability to change their own bandwidth parameters via a web-based application.

Service Flexibility
• Table interface, of Contents the provider can offer the customer different types of services, such With an Ethernet • Index transparent LAN service (TLS), Voice over IP (VoIP), and so on, with minimal as Internet access, Metro Ethernet operational overhead. Each service is provided over its own virtual LAN (VLAN) and is switched differently in BySam Halabi the network. The different services can be sold over the same Ethernet interface or, alternatively, each service can have a separate physical interface.
Publisher: Cisco Press

Lower Pricing Model ISBN: 1-58705-096-X
Pages: 240

Pub Date: October 01, 2003

The initial claims for the metro Ethernet service were very aggressive. Some of the early marketing campaigns claimed "twice the bandwidth at half the price." The quotes for 100-Mbps Ethernet connections initially ranged from $100 per month to $5000 per month depending on which carrier you talked to and at what time of the day you talked to them. Table 1-1 compares The definitive guide to Enterprise and Carrier Metro sample pricing for Ethernet and T1/T3 services. The Ethernet Ethernet applications. pricing might vary widely depending on the region and how aggressive the carrier gets. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to Table 1-1. Sample Pricing Comparison for Ethernet Versus T1/T3 understand the concepts Private-Line Service Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Greenfield Incumbent Metro 1.5 Mbps networks at ~$500/month will emerge as the next area T1 of(1.5 growth Mbps) for at the ~$750/month networking industry and will represent a major shift in how data services are offered to businesses and residential customers. 3 Mbps at has ~$750/month 2 * T1 at ~$1500 The metro always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability for voice. Carriers will have to 45 Mbps at ~$2250/month T3 (45 Mbps) at needs ~$6000/month go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational The Challenges and business of the model Greenfield that will Operators allow the incumbent carriers to transform the metro to offer enhanced data services. The BLECs and metro Ethernet carriers have encountered many challenges in their business Metro from Cisco their Press looks at thecaused deployment of them metro data services from a the holistic model Ethernet that have hindered success and a lot of to cease to exist after view. It describes the current metro, which is based on TDM technology, and discusses the telecom downturn. This section explores several of those challenges. drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers The Fight for of the Building Riser With a changing mix of transport technologies, the book to the delivery metro data services. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual Delivering Ethernet private connections local area networks to the MTU (VLAN), offices virtual requires private having LAN access services to the (VPLS), building traffic riser, engineering, which means and dealing MPLS with and the Generalized building owner—although MPLS (GMPLS). there are regulations that prevent building owners from refusing to allow access to providers. The BLECs, who normally manage to have the first access to the building, have the early field advantage in capturing real estate in the basement and the riser. Of course, how much real estate becomes available or unavailable to other BLECs who are competing for the same MTU usually depends on what percentage of the profits the building owner is receiving.

Cost of Overbuilding the Network
Because many providers in the past operated on the "build it and they will come" theory, millions of dollars were spent on overbuilding the network, which consisted of
• •
BySam Halabi

Table of Pulling fiber in Contents the riser Index

Metro Building Ethernet

the last-mile connectivity

Building the core metro network

Publisher: Cisco Press A challenge for the BLECs is to figure out how much connectivity they need inside the building. PubBLECs Date: October 2003 Many have 01, deployed as many connections as possible in the building on the hope that the BLECs ISBN: will attract customers. This model has, again, resulted in a lot of money spent with no 1-58705-096-X returnPages: on investment, forcing many BLECs out of business. 240

The premise of delivering services to customers in hours and days rather than months is made under the assumption that the BLEC has control of the network facilities inside and outside the building. The perfect solution is to have the BLEC lease or own fiber connections into the building. However, only about five percent of buildings in a metro area have access to fiber, The definitive to Enterprise and Carrier Metro Ethernet applications. while the rest guide can only be accessed via copper T1 and DS3 lines. Many BLECs are looking for the "low-hanging fruit," buildings that are already connected via fiber. In many cases, the BLECs try to have arrangements with utility companies to pull fiber into the buildings using existing Discover the latest developments in metro networking, Ethernet, and MPLS services and conduits. In the cases where fiber passes across the building and not into the buildings, the what they can do for your organization BLECs have to share the cost of digging up the streets with building owners or utility companies. The challenge is that the first BLEC to askthat for access into a building has to shareof the of to Learn from the easy-to-read format enables networking professionals allcost levels digging the trench, while the BLECs who come after can easily have access to the existing understand the concepts conduit. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam For buildings that couldn't haveRouting fiber connectivity, the BLECs had to rely on existing copper T1 Halabi, author of Internet Architectures and DS3 lines to deliver bandwidth into the building. So although the BLECs were competing with the ILECs, they still hadas tothe rely on them to growth providefor the copper lines atindustry the ILECs' slow Metro networks will emerge next area of the networking and will pace of operation. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has The metro carriers that building the metro edge and core infrastructure sunk a lot of to been built to handle theare stringent reliability and availability needs for voice. have Carriers will have money into buying or leasing the fiber that connects the different points of presence. Many metro go through fundamental shifts to equip the metro for next-generation data services demanded providers have locked themselves into multimillion-dollar leases based on the hope that by enterprise customers and consumers. This is not only afiber technology shift, but also a shift in the their business will grow to fill up the big pipes. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernetand from Cisco Press looks at the deployment of metro data services from a holistic The Breadth Reach of Services view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will with face the in transforming the metro to address data services. Metro carriers have also struggled different types of services that they offer and whether the service is offered on a regional or national basis. High-end customers such as large Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers enterprises and financial institutions usually use a one-stop shop: one provider offering local and to the delivery of metro data services. With a changing mix of transport technologies, the book national connectivity with different types of services, such as Frame Relay or ATM VPN services. then examines current and emerging trends, and delves into the role of virtual private networks An Ethernet-only service approach with no national coverage isn't too attractive. This has forced (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic the metro providers to remain as niche players that do not have the support and reach that the engineering, and MPLS and Generalized MPLS (GMPLS). incumbents have.

The Pricing Model

The cheap Ethernet connectivity pricing model could not be sustained. High-speed connections between 10 and 100 Mbps require a higher-speed backbone, which is expensive to build and manage. Also, the greenfield providers were still building up their customer base, and the low Ethernet pricing model did not help with a very small customer base. So Ethernet pricing for 100-Mbps connections was across the map and a trial-and-error process with prices varying by thousands of dollars depending on who you talk to.
• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

The U.S. Incumbent Landscape
While the greenfield operators were fast to build their metro networks, the U.S. incumbents took a sit-and-watch approach to see how the market would shake out. If the greenfield metro Ethernet model were to succeed, it would start stealing customers from the incumbents, thereby • of Contents affecting the Table deployment of their private-line services. Threatened by the newcomers, the RBOCs • Index and IXCs, such as SBC, Verizon, Bellsouth, Qwest, and MCI, initiated requests for information Metro Ethernet (RFIs) to solicit information from vendors about how to deliver Ethernet services in the metro.
BySam Halabi

The challenges the incumbents face in deploying metro Ethernet are very different than the challenges of the greenfields. This section discusses some of those challenges, including the Publisher: Cisco Press following:
Pub Date: October 01, 2003 ISBN: 1-58705-096-X

Existing legacy TDM infrastructure Pages: 240 Building an all-Ethernet data network Pricing the services The definitive guide to Enterprise and Carrier Metro Ethernet applications. Regulations Discover the latest developments in metro networking, Ethernet, and MPLS services and

Existing Legacy Infrastructure what they can doTDM for your organization

Learn from the easy-to-read format that enables networking professionals of all been levels to The U.S. metro is entrenched in TDM technology, and billions of dollars have already spent understand the concepts on building that network. Anyone who intends to build a new service has to consider the existing infrastructure. As inefficient as it may seem, building an Ethernet service over the legacy Gain from the experience of industry innovator best-selling Cisco author, Sam infrastructure might be the only viable way for some and incumbents to make aPress first entry into the Halabi, author of Internet Routing Architectures metro Ethernet business. Many of the operational models have already been built for the SONET network. Operators know how to build the network, how to manage and maintain it, and how to Metro networks will emerge as the next area of growth for the networking industry and will deliver a service and bill for it. The incumbents have the challenge of adopting their existing represent a major shift in how data services are offered to businesses and residential customers. discipline to the metro Ethernet model. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Building an All-Ethernet Data Network by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced dataU.S. services. Alternatively, some incumbents have opted (after many internal debates) to build an allEthernet network tailored for data services. However, as of the writing of this book, none of Metro networks Ethernet from Press looks at the deployment metrodealt data with services from a holistic these have Cisco materialized. Incumbents, who haveof always SONET technology, view. Itnot describes the currentEthernet metro, which is based on TDM technology, and discusses the and still do quite understand networks. Incumbents normally build their networks drivers and challenges will face new in transforming the metro to address data services. services to tailor to thecarriers masses, so any technology they deploy needs to scale to support thousands of customers nationwide. With Ethernet's roots in enterprise networks, a big gap still Metro discusses the adoption of metro Ethernet services and switches, how that has led carriers exists Ethernet between what the incumbents need and what existing Ethernet or existing to the delivery of metro data services. With a changing mix of transport technologies, the Ethernet standards, have to offer. Incumbents are also unfamiliar with how to manage an book then examines current and emerging trends, and delves into the role of virtual private networks Ethernet network, price the service, and bill for it. All of these factors have contributed to the (VPN), virtual private local delay in the deployment of area such networks networks.(VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). The deficiencies in Ethernet technology and Ethernet standards in dealing with the metro scalability and availability requirements were one of the main reasons for the proliferation of MPLS in the metro. This topic will be explained in more detail in Chapter 4, "Hybrid L2 and L3 IP/MPLS Networks."

Pricing the Service
For the incumbents, pricing the metro Ethernet services is an extremely challenging exercise. Incumbents that are selling T1 and DS3 connectivity services would be competing with themselves by offering Ethernet services. A very aggressive Ethernet pricing model would jeopardize the sales of T1 and DS3 lines and disrupt the incumbent's business model.
•

For incumbents selling T1/E1 and DS3 services, their Ethernet pricing model has to do the • Index following to succeed: Metro Ethernet
BySam Halabi

Table of Contents

Move hand in hand with existing pricing for legacy services to avoid undercutting the legacy services. Publisher: Cisco Press Offer different levels of services with different price points, in addition to the basic ISBN: 1-58705-096-X connectivity service. Metro Ethernet services present a good value proposition for both the Pages: 240 customer and carrier. The customer can enjoy enhanced data services at higher performance levels, and the carrier can benefit from selling services that it otherwise wouldn't have been able to sell with a simple TDM connection. So the carrier can actually sell the Ethernet connection at a lower price than the legacy connection, based on the hope that the additional services will eventually result in a more profitable service than the The definitive legacy services. guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and
Pub Date: October 01, 2003

The what Incumbent Regulations they can do for your organization

Learn from the easy-to-read format that of enables professionals of all levels Another area that challenges the deployment metro networking Ethernet services in the U.S. are the to understand theincumbent concepts carriers have and the delineation between the regulated and regulations that the unregulated operation inside the same carriers. The regulated portions of the incumbents deal Gain from the experience of and industry best-selling Press author, Sam of mainly with transport equipment haveinnovator rules and and guidelines aboutCisco the use and the location Halabi, author of Internet Routing Architectures data switching equipment. The unregulated portion of the incumbent normally has enough flexibility to deploy a mix of hybrid data switching and transport equipment without many ties. Metro networks will emerge as the next area of growth for the networking industry and will represent a major have shift in how data services offered to businesses and residential customers. These regulations created a big barrier are inside the incumbents and have created two The metro has always been a challenging environment for delivering data services because different operational entities to deal with data and transport. The deployment of new data it has been built to handle the stringent reliability and voice. Carriers have to services such as metro Ethernet will prove to be availability challengingneeds in thefor U.S. because suchwill services go through fundamental shifts to equip the metro for next-generation data services demanded require a lot of coordination between the data operation and the transport operation of the same by enterprise customers and consumers. This is not only a technology shift, but also a shift in the incumbent carrier. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

The International Landscape
In 2000, while the U.S. market was bubbling with greenfield operators building their metro networks and challenging the almighty RBOCs and IXCs, the metro Ethernet market was taking its own form and shape across the globe. What was different about the rest of the world was the • Table of Contents lack of venture capital funding that had allowed new greenfield providers to mushroom in the • Index U.S.
Metro Ethernet BySam Halabi

The European Landscape
Publisher: Cisco Press Pub Date: the October 01, 2003 In Europe, first activities in metro Ethernet occurred in Scandinavia, specifically Sweden. ISBN: 1-58705-096-X Telia, the largest Swedish telecom provider, had submitted an RFI for metro Ethernet services. UnlikePages: the U.S., 240 where the providers were focusing on T1 private-line replacement, the target application in Sweden was residential. Many MDU apartment complexes were located in concentrated residential areas, and many of the new developments had fiber already deployed in the basements of the MDUs. Ethernet services seemed like the perfect vehicle to deliver valueadded services such as converged voice, data, and video applications. A single Ethernet connection to an MDU could provide Internet access, VoIP, video on demand, and so on. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Also across Europe, a handful of greenfield operators had very aggressive plans to deploy metro Ethernet services, but most faced the same challenges as the U.S. greenfield operators. In Discover the latest developments in metro networking, Ethernet, and MPLS services and pockets of Europe such as Italy, large players such as Telecom Italia were experimenting with an what they can do for your organization all-Ethernet metro for residential customers. Learn from the easy-to-read format that enables networking professionals of all levels to In general, however, the European metro is entrenched in SDH technology and, like the U.S., understand the concepts has invested in legacy TDM deployments. This puts the big European providers in the same challenging position as the U.S. incumbents in dealing with service cannibalization and the cost Gain from the experience of industry innovator and best-selling Cisco Press author, Sam of a new buildout. However, Europe differs from the U.S. in that it doesn't have stringent Halabi, author of Internet Routing Architectures regulations that require a strict boundary between the operation of data switching equipment and SDH transport which could play a big role the shift toward metroand Ethernet Metro networks willequipment, emerge as the next area of growth for in the networking industry will buildouts. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded The Asian Landscape by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to The Ethernet offermetro enhanced data landscape services. in Asia is very different than in the U.S. and Europe. Japan, Korea, and China will prove to be the major players in the deployment of all-Ethernet metro services. One offrom the major reasons is that these countries of haven't as much inaSONET or Metro Ethernet Cisco Press looks at the deployment metro invested data services from holistic SDH and, thus, have a cleaner slate than the U.S. and Europe from which to deploy new data view. It describes the current metro, which is based on TDM technology, and discusses the services in the metro. carriers will face in transforming the metro to address data services. drivers and challenges Many Ethernet deployments have been announced by big Metro metro Ethernet discusses the adoption ofalready metro Ethernet services and and deployed how that has ledtelecom carriers providers such of as metro Korea data Telecom SK and others. China will emerge as a big player in this to the delivery services. With a changing mixalso of transport technologies, the book market after the restructuring of China Telecom into different entities, China Netcom, then examines current and emerging trends, and delves into the role of virtual privateUnicom, networks and Railcom. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). In Japan, tough competition between telecom providers has driven the cost of private-line services lower than in most other countries. Japan is also a leader in all-metro Ethernet deployments for multimedia services.

A Data View of the Metro
A data view of the metro puts in perspective the different metro services and how they are offered by the different providers.
• Table of Contents Figure 1-6 shows a view of the metro with the emphasis on the data access, data aggregation, • Index and service delivery. As you can see, the metro is divided into three segments:
Metro Ethernet BySam Halabi

Metro access— This segment constitutes the last-mile portion, which is the part of the network that touches the end customer. For business applications, for example, access Publisher: Cisco Press equipment resides in a closet in the basement of the enterprise or MTU.
Pub Date: October 01, 2003

Metro edge— This segment constitutes the first level of metro aggregation. The ISBN: 1-58705-096-X connections leaving the buildings are aggregated at this CO location into bigger pipes that Pages: 240 in turn get transported within the metro or across the WAN. Metro core— This segment constitutes a second level of aggregation where many edge COs are aggregated into a core CO. In turn, the core COs are connected to one another to form a metro core from which traffic is overhauled across the WAN. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Figure 1-6. Data View of the Metro
Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization
[View full size image]

Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. The terminology and Cisco manyPress variations can beof confusing. In services some cases, is only Metro Ethernet from looksof atthe themetro deployment metro data fromthere a holistic one level of aggregation; hence, the building connections are aggregated into one place and view. It describes the current metro, which is based on TDM technology, and discusses the then directly connectedcarriers to a core router. Intransforming other scenarios, the metro core CO, sometimes drivers and challenges will face in the metro to address data services.called the metro hub, co-locates with the wide-area POP. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Metro Services
The metro services vary depending on the target market—commercial or residential—and whether it is a retail service or a wholesale service. The following list gives a summary of some of the metro services that are promoted:
• •
BySam Halabi

Table of Contents Index

Metro Internet Ethernet

connectivity

Transparent LAN service (point-to-point LAN to LAN) or multipoint-to-multipoint LAN to LAN)

Publisher: Press L2VPNCisco (point-to-point Pub Date: October 01, 2003

LAN to network resources (remote data center) ISBN: 1-58705-096-X Extranet
Pages: 240

LAN to Frame Relay/ATM VPN Storage area networks (SANs) The definitive guide to Enterprise and Carrier Metro Ethernet applications. Metro transport (backhaul) VoIP Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Some of these services, such as Internet connectivity and TLS, have been offered for many years. The difference now is that these services are provided with Ethernet connectivity, andto the Learn from the easy-to-read format that enables networking professionals of all levels carriers are moving toward a model in which all of these services can be offered on the same understand the concepts infrastructure and can be sold to the same customer without any major operational overhead. This introduces Gain from an theexcellent experience value of industry proposition innovator to both and thebest-selling customer and Cisco thePress carrier. author, The services Sam are provisioned Halabi, author through of Internet transporting Routing the Architectures application over point-to-point or multipoint-tomultipoint L2 connections. The following sections discuss some of these services in greater Metro networks will emerge as the next area of growth for the networking industry and will detail. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to LAN to Network Resources go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Earlier, in the section "The Metro Network," you saw how Internet service can be delivered byto operational and business model that will allow the incumbent carriers to transform the metro installing at thedata customer premises an Ethernet connection rather than a T1 TDM connection. offer enhanced services. After the Ethernet connection is installed at the end customer, the ILEC can sell different services to the Ethernet customer, such as LAN to network resources. An example of data such services a service is one that Metro from Cisco Press looks at the deployment of metro from a holistic enables an enterprise to back metro, up its data in is a remote and secure locationand for disaster recovery. view. It describes the current which based on TDM technology, discusses the drivers and challenges carriers will face in transforming the metro to address data services. Figure 1-7 shows that in addition to Internet service, the customer can have a data backup and disaster recovery service that constantly data across theand metro. Metro Ethernet discusses the adoption of backs metroup Ethernet services how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current Figure and emerging and delves intoResources the role of virtual private networks 1-7. trends, LAN to Network (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

For new data networks in which the connectivity is done via gigabit and 10 gigabit pipes, the metro can be transformed into a high-speed LAN that offers bandwidth-intensive applications that would not normally be feasible to deploy over legacy TDM infrastructure. The definitive guide to Enterprise and Carrier Metro Ethernet applications. As previously mentioned, the service in the metro will take many shapes and forms depending on the target customer. The same LAN to network resources model could be applied toward Discover the latest developments in metro networking, Ethernet, and MPLS services and residential applications, enabling the ILECs to start competing with cable companies in what they can do for your organization distributing multimedia services. In a residential application, video servers would be located in a metro POP and residential MDU customers could access high-speed digital videoof on demand over Learn from the easy-to-read format that enables networking professionals all levels to an Ethernet connection. While these services still seem futuristic in the U.S., the international understand the concepts landscape soon could be very different in Europe (particularly Sweden), Japan, and Korea, where the fast deployment of Ethernet networks already making these applications a reality. Gain from the experience of industry is innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will Ethernet L2VPN Services represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has You may have noticed that many of the services mentioned are pure L2 services that offer been built to handle the stringent reliability and availability needs for voice. Carriers will have to connectivity only. This is similar to legacy Frame Relay and ATM services, where the Frame go through fundamental shifts to equip the metro for next-generation data services demanded Relay/ATM connection offers a pure L2 pipe and the IP routed services can ride on top of that by enterprise customers and consumers. This is not only a technology shift, but also a shift in the pipe. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Figure 1-8 shows a carrier deploying an Ethernet L2VPN service. The carrier network behaves as an L2 Ethernet switch that offers multipoint-to-multipoint connectivity between the different Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic customer sites. The customer can benefit from running its own control plane transparently over view. It describes the current metro, which is based on TDM technology, and discusses the the carrier's network. The customer routers at the edge of the enterprise could exchange routing drivers and challenges carriers will face in transforming the metro to address data services. protocols without interference with the carrier routing, and the carrier would not have to support any of Ethernet the customer's IP addressing. An observation is that the has carrier's network Metro discusses the adoption ofimportant metro Ethernet services and while how that led carriers behaves like an L2 Ethernet switch, the underlying technology and the different control planes to the delivery of metro data services. With a changing mix of transport technologies, the book used in the carrier network are not necessarily based on into Ethernet or a Layer 2 control then examines current and emerging trends, and delves the role of virtual private plane. networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized Figure 1-8. MPLS L2VPN (GMPLS).services

[View full size image]

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Ethernet Access and Frame Relay Comparison
Frame Relay VPN services have been widely accepted and have proven to be very cost effective compared to point-to-point private-line service. In essence, Ethernet services can be considered the next-generation of Frame Relay because they provide most of the benefits of Frame Relay • Table of Contents with better scalability as far as providing higher bandwidth and multipoint-to-multipoint • Index connectivity services. The following list shows some of the similarities and dissimilarities Metro Ethernet between an Ethernet and a Frame Relay service:
BySam Halabi

Publisher: Cisco Press

Interface speed— Frame Relay interface speeds range from sub-T1 rates up to OCn speeds. However, Frame Relay has been widely deployed at the lower sub-T1, T1, and DS3 Pub Date: October 01, 2003 interface can run at up to 10 Gbps. speeds. An Ethernet
ISBN: 1-58705-096-X

Last-mile Pages: 240 connectivity— Ethernet services will find better acceptance in on-net deployments (where fiber reaches the building), irrespective of the transport method (as will be explained in the next chapter). Frame Relay has the advantage of being deployed in off-net applications over existing copper T1 and DS3 lines, which so far constitutes a very high percentage of deployments. There are existing efforts in forums, such as the Ethernet in the First Mile (EFM) forum, to run Ethernet directly over existing copper lines. It is The definitive guide to Enterprise and Carrier Metro Ethernet applications. unknown at this point whether such a deployment would find acceptance compared to a traditional Frame Relay service. Discover the latest developments in metro networking, Ethernet, and MPLS services and Virtual circuit support— Both Ethernet and Frame Relay offer a multiplexed interface that what they can do for your organization allows one customer location to talk to different locations over the same physical interface. The VLAN notion of Ethernet is similar to enables the Frame Relay permanent virtual (PVC). Learn from the easy-to-read format that networking professionals of circuit all levels to understand the concepts Multipoint connectivity— An obvious difference between Frame Relay and Ethernet is that Frame Relay virtual circuits are point-to-point Any Cisco point-to-multipoint Gain from the experience of industry innovator and circuits. best-selling Press author, or Sam multipoint-to-multipoint connectivity between sites is done via the provisioning of multiple Halabi, author of Internet Routing Architectures point-to-point PVCs and routing between these PVCs at a higher layer, the IP layer. With Ethernet, constitutes a broadcast domain, sites can share and multipointMetro networksthe willVLAN emerge as the next area of growth forand themany networking industry will to-multipoint connectivity at L2. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has interface— A very important benefit that both Frame Relay Ethernet offer is the to been L2 built to handle the stringent reliability and availability needs forand voice. Carriers will have ability to keep the separation between the network connectivity at L2 and the higher-level go through fundamental shifts to equip the metro for next-generation data services demanded IP application, including L3 routing. This This is allows the a customer to have control over its in the by enterprise customers and consumers. not only technology shift, but also a shift existing L2 or L3 network and keep a demarcation between the customer's network and the operational and business model that will allow the incumbent carriers to transform the metro to carrier's network. offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
The proliferation of data services in the metro is already taking place. You have seen in this chapter how metro data services and specifically Ethernet services are making their move into the metro. The greenfield metro operators have had quite an influence on this shift by putting • Table of Contents pressure on traditional metro operators, such as the ILECs. While metro Ethernet is evolving • slowly in theIndex U.S. due to legacy TDM deployments and regulations, it has found good success in Metro Ethernet different parts of the world, especially in Asia and Japan. Metro Ethernet services offer an excellent value proposition both to service providers and to businesses and consumers. Metro By Sam Halabi Ethernet services will reduce the recurring cost of service deployment while offering much flexibility in offering value-added data services. Publisher: Cisco Press
Pub Date: October 01, 2003 Metro Ethernet services do not necessitate an all-Ethernet L2 network; rather, they can be ISBN: 1-58705-096-X deployed over different technologies such as next-generation SONET/SDH and IP/MPLS Pages: 240 networks. Chapter 2, "Metro Technologies," goes into more details about the different technologies used in the metro.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 2. Metro Technologies
This chapter covers the following topics:
• •

Ethernet over SONET/SDH (EOS)
Index

Table of Contents

Metro Resilient Ethernet BySam Halabi

Packet Ring (RPR)

Ethernet Transport Metro Ethernet services and applications do not necessarily require Ethernet as the underlying Pub Date: October 01, 2003 transport technology. The metro can be built on different technologies, such as
ISBN: 1-58705-096-X Pages: 240 Publisher: Cisco Press

Ethernet over SONET/SDH (EOS) Resilient Packet Ring (RPR) Ethernet Transport The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Ethernet over SONET/SDH
Many incumbent carriers in the U.S. and Europe have already spent billions of dollars building SONET/SDH metro infrastructures. These carriers would like to leverage the existing infrastructure to deliver next-generation Ethernet services. For such deployments, bandwidth • Table of Contents management on the network is essential, because of the low capacity of existing SONET/SDH • Index rings and the fact that they can be easily oversubscribed when used for data services.
Metro Ethernet

Incumbents BySam Halabi who want to deploy EOS services face tough challenges. Traditionally, for RBOCs and ILECs in the U.S., there is a clear-cut delineation between transport and data. The regulated part of the organization deals with transport-only equipment, not data equipment. With EOS, the Publisher: Cisco Press equipment vendors blur the line between data and transport, which creates a problem for the Pub Date: October 01, 2003 adoption of the new technology. So, it is worth spending some time explaining the EOS ISBN: 1-58705-096-X technology itself.
Pages: 240

The benefit of EOS is that it introduces an Ethernet service while preserving all the attributes of the SONET infrastructure, such as SONET fast restoration, link-quality monitoring, and the use of existing SONET OAM&P network management. With EOS, the full Ethernet frame is still preserved and gets encapsulated inside the SONET payload at the network ingress and gets removed at the egress. The definitive guide to Enterprise and Carrier Metro Ethernet applications. AsFigure 2-1 shows, the entire Ethernet frame is encapsulated inside an EOS header by the EOS function of thethe endlatest system at the ingress. The Ethernet frame is then mapped onto the Discover developments in metro networking, Ethernet, and MPLS services and SONET/SDH Synchronous Payload Envelope (SPE) and is transported over the SONET/SDH ring. what they can do for your organization The Ethernet frame is then extracted at the EOS function on the egress side. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Figure 2-1. Ethernet over SONET Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow Ethernet the incumbent carriers to transform network: the metro to There are two standardized ways to transport frames over a SONET/SDH offer enhanced data services. MetroLAPS— Ethernet from Cisco looks at the deployment ofis metro data services from a holistic Ethernet overPress the Link Access Procedure SDH defined by the ITU-T, which view.published It describes the current metro, which is based TDM technology, and discusses the the X.86 standard in February 2001. on LAPS is a connectionless protocol similar to drivers and challenges carriers will (HDLC). face in transforming the metro to address data services. High-Level Data Link Control MetroGFP— Ethernet discusses the Procedure adoption of Ethernet services and how that has led carriers Generic Framing ismetro also an ITU standard that uses the Simple Data Link to the delivery of metro data services. With a changing mix of transport technologies, the book (SDL) protocol as a starting point. One of the differences between GFP and LAPS is that then examines current and emerging trends, and than delves into thesuch role of private networks GFP can accommodate frame formats other Ethernet, as virtual PPP, Fiber Channel, fiber (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic connectivity (FICON), and Enterprise Systems Connection (ESCON). engineering, and MPLS and Generalized MPLS (GMPLS). The EOS function can reside inside the SONET/SDH equipment or inside the packet switch. This creates some interesting competing scenarios between switch vendors and transport vendors to offer the Ethernet connection. Figures 2-2,2-3, and 2-4 show different scenarios for the EOS connection. In Figure 2-2, the

EOS function is inside the ADM. This is normally done via a combination framer/mapper that supports EOS and is placed on a line card or daughter card inside the ADM. The EOS mapping function adds an X.86 or GFP wrapper around the whole Ethernet frame, and the framing function encapsulates the frame in the SONET/SDH SPE. From then on, the SONET/SDH SPE is transported across the SONET/SDH ring and gets peeled off on the egress side. ADMs that contain the EOS function plus other functions such as virtual concatenation (discussed in the next section) are called next-generation ADMs. Figure 2-3 places the EOS function inside the switch. • Table of Contents
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Metro Ethernet BySam Halabi

Index

Figure 2-2. EOS Function Inside the ADM

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 2-3. EOS Function Inside the Switch

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will The difference here is that the data equipment and the transport equipment are two different represent a major shift in how data services are offered to businesses and residential customers. entities that can be owned by different operational groups within the same carrier. This makes it The metro has always been a challenging environment for delivering data services because it has much easier for regulated and unregulated entities within the carrier to deploy a new service. been built to handle the stringent reliability and availability needs for voice. Carriers will have to The regulated group's sole responsibility is to provision SONET/SDH circuits, as they would do go through fundamental shifts to equip the metro for next-generation data services demanded for traditional voice or leased-line circuits. The unregulated group in turn deploys the higherby enterprise customers and consumers. This is not only a technology shift, but also a shift in the layer data services. It is also worth mentioning that in this scenario, the Ethernet switch that operational and business model that will allow the incumbent carriers to transform the metro to delivers the data services has full control of the SONET/SDH tributaries. This is in contrast to offer enhanced data services. Figure 2-2, in which the SONET/SDH tributaries are terminated inside the ADM, and the Ethernet switch sees only a concatenated Ethernet pipe. Figure 2-4 combines the packet-switching, ADM, Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic and EOS functions in the same equipment. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. For equipment efficiency, this is the optimal solution; however, the deployment of such systems can be challenging if strict operational delineation between packet and transport exists. Such Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers deployments are occurring in the U.S. by smaller competitive telecom providers and by the to the delivery of metro data services. With a changing mix of transport technologies, the book unregulated portion of the RBOCs/ILECs that do not have many restrictions about data versus then examines current and emerging trends, and delves into the role of virtual private networks transport. Deployments of such systems in Europe are more prevalent because Europe has fewer (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic restrictions than the U.S. engineering, and MPLS and Generalized MPLS (GMPLS). EOS introduces some bandwidth inefficiencies in deploying metro Ethernet services because of the coarse bandwidth granularity of SONET/SDH circuits and the bandwidth mismatch with the sizes of Ethernet pipes. Virtual concatenation (VCAT) is a mechanism used to alleviate such inefficiencies, as discussed next.

Figure 2-4. EOS and Switching Functions Inside the ADM

The Role of Virtual Concatenation
Virtual concatenation is a measure for reducing the TDM bandwidth inefficiencies on SONET/SDH rings. With standard SONET/SDH concatenation, SONET/SDH pipes are provisioned with coarse granularity that cannot be tailored to the actual bandwidth requirement. The TDM circuits are either too small or large to accommodate the required bandwidth. On a SONET/SDH ring, • Table oftoo Contents once the circuit is allocated, the ring loses that amount of bandwidth whether the bandwidth is • Index used Ethernet or not. Metro
BySam Halabi

Appendix A, "SONET/SDH Basic Framing and Concatenation," briefly describes SONET/SDH and the different terminology you see throughout this chapter.
Publisher: Cisco Press

With VCAT, a number of smaller pipes are concatenated and assembled to create a bigger pipe Pub Date: October 01, 2003 that carries more data per second. Virtual concatenation is done on the SONET/SDH layer (L1) ISBN: 1-58705-096-X itself, Pages: meaning 240 that the different individual circuits are bonded and presented to the upper network layer as one physical pipe. Virtual concatenation allows the grouping of n * STS/STM or n * VT/VC, allowing the creation of pipes that can be sized to the bandwidth that is needed. Figure 2-5 highlights the bandwidth efficiency that VCAT can provide. If standard concatenation is used and the bandwidth requirement is for 300 Mbps (about six STS-1s), the carrier has the The definitive guide tomultiple Enterprise and Carrier Metro Ethernet applications. option of provisioning DS3 interfaces and using packet multiplexing techniques at the customer premises equipment (CPE) to distribute the traffic over the interfaces. (Note that a DS3 interface is the physical interface that runs at a 45-Mbps rate, while an STS-1 is a SONET Discover the latest developments in metro networking, Ethernet, and MPLS services and envelope that can carry 50 Mbps.) Provisioning multiple DS3s at the CPE is normally inefficient, what they can do for your organization because it increases the cost, does not guarantee the full bandwidth (because of packet loadsharing techniques), and restricts the packet flow to 45 Mbps (because the individual physical Learn from the easy-to-read format that enables networking professionals of all levels to circuits are restricted to DS3 bandwidth). The other alternative is for the carrier to allocate a full understand the concepts OC12 (12 STS-1s); this causes the carrier to lose revenue from selling six STS-1s, because they are allocated to the a particular customer and innovator cannot be and used for other customers onauthor, the ring. With Gain from experience of industry best-selling Cisco Press Sam virtual concatenation, carrier can provision a 300 Mbps pipe by bonding six STS-1s as one Halabi, author of the Internet Routing Architectures big pipe—hence no wasted bandwidth. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in Figure how data 2-5. services are offered to businesses and residential customers. Virtual Concatenation The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 2-6 shows an example of how multiple services such as Ethernet connectivity services and

traditional TDM services can be carried over the same SONET/SDH infrastructure. If the SONET/SDH equipment supports VCAT, a Gigabit Ethernet interface can be carried over a concatenated 21 STS-1 pipe, another Fast Ethernet (FE) 100-Mbps interface can be carried over two STS-1s, and a traditional DS3 interface can be carried over a single STS-1. In many cases, the speed of the Ethernet interface does not have to match the speed on the SONET/SDH side.

Figure 2-6. Transporting Ethernet over SONET
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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. A Fast Ethernet 100-Mbps interface, for example, can be carried over an STS-1 (50 Mbps), two Discover the latest developments in metro networking, Ethernet, and MPLS servicesof and STS-1s, or three STS-1s. To handle this oversubscription, throttling of data and queuing what they can do for your organization packets or some kind of data backoff need to happen to minimize packet loss. from the easy-to-read formatdown that enables networking all levels to Most Learn rings today support channelization to the STS-1 (DS3) professionals level and can of cross-connect understand the For concepts circuits at that level. T1 services, M13 multiplexers are used to aggregate multiple T1 lines to a DS3 before transporting them on the ring. SONET/SDH equipment that operates at the VT/VC Gain from the experience innovator and best-selling Cisco Press author, Sam level is starting to be deployed of byindustry some RBOCs, which means that with virtual concatenation, Halabi, author of Internet Routing Architectures circuits of n * VT/VC size can be provisioned. Metro networks will functions emerge as the next area ofat growth for the and will The EOS and VCAT are implemented the entry andnetworking exit points industry of the SONET/SDH represent a major shift in how data services are offered to businesses and residential customers. infrastructure, and not necessarily at every SONET/SDH station along the way. In Figure 2-6, The metro has always been a challenging environment for delivering data services because it has ADMs 1 and 2 support the EOS and VCAT functions, while the cross-connect (XC) that connects been built to handle the stringent reliability and availability needs for voice. Carriers will have the two rings functions as a traditional cross-connect. However, for VCAT to be effective, the to go through fundamental shifts equip metro next-generation data services demanded SONET/SDH equipment on the to ring has the to be able for to cross-connect the tributaries supported by by enterprise customers and consumers. This is not only a technology shift, but also a shift in the the VCAT; otherwise, the bandwidth savings on the ring are not realized. So, if the equipment on operational and business model of that will allow the incumbent carriers to transform the metro the ring supports the allocation STS-1 circuits and higher, the smallest circuit that can be to offer enhanced data services. allocated is an STS-1 circuit. If the terminating equipment supports VCAT to the VT 1.5 level (T1), a full STS-1 bandwidth is still wasted on the ring even if the CPE is allocated n * VT 1.5 via Metro Press looks at the deployment ofVCAT metro data to services a holistic VCAT. Ethernet In Figurefrom 2-6, Cisco for example, if ADMs 1 and 2 support down the VT from 1.5 (T1) level, view. It describes the current metro, which is based on TDM technology, and discusses and the cross-connect can cross-connect only at the STS-1 (DS3) level, the savings are the not drivers and challenges carriers will face in transforming the metro to address data services. realized. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Link Capacity Adjustment Scheme then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, Virtual concatenation and MPLS isand a powerful Generalized tool for MPLS efficiently (GMPLS). grouping the bandwidth and creating pipes that match the required bandwidth. However, the customer bandwidth requirement could change over time, which requires the SONET/SDH pipes to be resized. This could cause network disruption as more SONET/SDH channels are added or removed. Link Capacity Adjustment Scheme (LCAS) is a protocol that allows the channels to be resized at any time without disrupting the traffic or the link. LCAS also performs connectivity checks to allow failed links to

be removed and new links to be added dynamically without network disruption. The combination of EOS, VCAT, and LCAS provides maximum efficiency when deploying Ethernet services over SONET.

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NOTE Table of Contents
Index

MetroVirtual Ethernet concatenation

totally BySam Halabi

and EOS are orthogonal technologies, meaning that they are independent. EOS is a mapping technology that runs over standard concatenation and VCAT; however, the full benefits are achieved if done over the latter. Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X

Pages: 240 The following sections describe different scenarios in which EOS is used as a pure transport service or is applied in conjunction with packet switching.

EOS Used as a Transport Service

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Ethernet over SONET/SDH by itself is still a transport service with an Ethernet interface, similar to the traditional service with a T1, DS3, or OCn Ethernet, interface. and EOSMPLS offers what is and Discover theprivate-line latest developments in metro networking, services comparable to a point-to-point packet leased-line service. It provides an easy migration for what they can do for your organization carriers that sell transport to get their feet wet with Ethernet services. EOS is a "packet mapping" technology, not a "packet switching" technology, and does not offer the Learn from the easy-to-read format that enables networking professionals of packet all levels to multiplexing that is needed for the aggregation and deaggregation of services. To deliver understand the concepts enhanced switched data services, you need to introduce packet-switching functionality into the metro equipment. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures The lack of packet multiplexing for the EOS service and the fact that thousands of point-to-point circuits need to be the customers thenetworking central office (CO) create a Metro networks willprovisioned emerge as between the next area of growth and for the industry and will problem in aggregation of services in large-scale deployments. Each individual EOS circuit represent athe major shift in how data services are offered to businesses and residential customers. could be presented as a separate Ethernetenvironment interface in the CO. With thousands of customers The metro has always been a challenging for delivering data services because it has getting an to EOS circuit, the CO would have to terminate thousands of individual Ethernet been built handle the stringent reliability and availability needs for voice. Carriers will wires. have to Imagine if the Public Switched Network (PSTN) were still operating with each go through fundamental shifts Telephone to equip the metro for next-generation data services demanded customer line customers terminatedand inside the CO as a physical wire than as a logical circuit. This by enterprise consumers. This is not only arather technology shift, but also a shift in the would create a big patch-panel andallow a nightmare for provisioning and switching between operational and business model effect that will the incumbent carriers to transform the metro to circuits. This patch-panel effect presents a scalability limitation for large-scale EOS deployments, offer enhanced data services. as explained next. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Figure 2-7 shows a scenario in which which a carrier is using sell a basic Internet-connectivity view. It describes the current metro, is based on EOS TDMto technology, and discusses the service. A SONET/SDH metro access ring multiple and multitenant unit drivers and challenges carriers will face inconnects transforming the enterprise metro to address data services. (MTU) buildings to a CO location. Next-generation ADMs in the basements of the buildings Metro Ethernet discusses the adoption of metro Ethernet services and routers how that led carriers provide 100-Mbps Ethernet connections that connect to the individual athas each customer to the delivery of metro data services. With a changing mix of transport technologies, the book premise. The ring itself, in this example, allows channelization down to the VT 1.5 (T1) level, then examines current and emerging trends, and delves into the role of virtual private networks and each Ethernet connection is mapped to one or n * VT 1.5 circuits. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized (GMPLS). Figure 2-7. EOS MPLS Inside Transport Equipment

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

For every customer who is provisioned with an Ethernet interface, an Ethernet interface is extended out of the XC at the CO, because the XC works at the TDM level, and each circuit has to be terminated individually. The individual Ethernet interfaces are then connected to an Ethernet switch that aggregates the traffic toward the ISP router. This means that if a building has 20 The definitive to Enterprise and Carrier Metro Ethernet applications. customers, 20 guide different circuits have to be provisioned for that building and have to be terminated in the CO. If the CO supports 50 buildings with 20 customers per building, 1000 TDM circuits have to be provisioned, and hence 1000 Ethernet interfaces have to be terminated in the Discover the latest developments in metro networking, Ethernet, and MPLS services and CO. This model is very inefficient and does not scale well in terms of equipment or management. what they can do for your organization The XC will be loaded with physical Fast Ethernet interfaces, and the physical connectivity is unmanageable. solution for this problem is networking to introduce aggregation of techniques Learn fromThe the logical easy-to-read format that enables professionals all levels to inside the cross-connect using Ethernet VLANs and to aggregate multiple Ethernet circuits over a understand the concepts single Gigabit or 10 Gigabit Ethernet interface where each circuit is individually identified. While such techniques areexperience possible, they would mean moreand involvement of transport vendors on the Gain from the of industry innovator best-selling Cisco Press author, Sam data side, which is challenging an Architectures operational perspective, especially in the U.S. Halabi, author of Internet from Routing Figure 2-8 shows anemerge example in which the XC aggregates EOS circuits and overwill a single Metro networks will as the next area of growth for the thedifferent networking industry Ethernet interface that connects to an Ethernet switch. For this to happen, the XC needs to be represent a major shift in how data services are offered to businesses and residential customers. able to logically separate the individual EOS circuits when presenting them to the Ethernet The metro has always been a challenging environment for delivering data services because it has switch. This tothe be stringent done because the traffic sent from the Ethernet switch to thewill XC have over to been built toneeds handle reliability and availability needs for voice. Carriers the GE port needs to be tagged with the right circuit ID to reach the correct destination. One go through fundamental shifts to equip the metro for next-generation data services demanded method is to have the XC tagconsumers. individual circuits a VLAN ID before shift, sending traffic to in the by enterprise customers and This is with not only a technology butthe also a shift the Ethernet switch. Other current implementations put the whole Ethernet bridging function inside operational and business model that will allow the incumbent carriers to transform the metro to the XC itself to allow the multiple EOS streams to be aggregated over a single interface when offer enhanced data services. leaving the transport equipment. This has all the signs of fueling an ongoing industry debate over what functions in which equipment as the data and services transport vendors start Metro Ethernet fromreside Cisco Press looks at the deployment ofvendors metro data from a holistic stepping on each other's toes. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks [View full size image] (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 2-8. EOS Aggregation Inside Transport Equipment

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

An obvious benefit of a transport service that gives each customer its own TDM circuit is that the customer is guaranteed the full bandwidth. The metro carriers that sell SONET/SDH circuits have dealt with this model for years and know full well how to substantiate the SLAs they sell. When this model is used with VCAT, which enables carriers to tailor the size of the circuit to the The definitive guide to Enterprise andgreat Carrier Metro Ethernet applications. customer's need, carriers can realize bandwidth efficiency and offer firm QoS guarantees. However, you need to weigh this with the complexity of managing the multitude of additional TDM circuits that have to be provisioned, because all these new circuits need to be crossDiscover the latest developments in metro networking, Ethernet, and MPLS services and connected in the network. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts EOS with Packet Multiplexing at the Access Gain from the experience of industry innovator and best-selling Cisco Press author, Sam The previous example assumes that each customer in the building gets an individual TDM circuit. Halabi, author of Internet Routing Architectures Another alternative is for the service provider to introduce packet multiplexing in the access switch. The service can achieve cost of savings by having multiple customers share the Metro networks will provider emerge as the next area growth for the networking industry and will same TDM circuit. These cost savings translate into lower cost for the basic connectivity service represent a major shift in how data services are offered to businesses and residential customers. provided to thealways customer. The metro has been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Figure 2-9 shows a scenario where, in the same 50-building metro, each building has an STS-1 go through fundamental shifts to equip the metro for next-generation data services demanded (DS3) link that is shared by all 20 customers in each building. This greatly reduces the number by enterprise customers and consumers. This is not only a technology shift, but also a shift in the of TDM circuits that have to be provisioned, because all customers in the same building share the operational and business model that will allow the incumbent carriers to transform the metro to same STS-1 circuit toward the CO. This reduces the total TDM circuits from 1000 to 50. Notice offer enhanced data services. that 50 Ethernet ports still need to be terminated in the CO if the cross-connect does not have tagging or packet-multiplexing capabilities. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the 2-9. EOS with Packet Multiplexing at the Access drivers and Figure challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With [Viewafull changing size image] mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 1-58705-096-X PacketISBN: multiplexing in the last mile is yet another incremental step that the metro carriers would Pages: 240 to move in the direction of delivering switched Ethernet services. Although this have to adopt model reduces the number of TDM circuits that need to be provisioned, it introduces issues of circuit oversubscription and SLA guarantees. Traffic from multiple customers would be fighting for the STS-1 link, and one customer with a Fast Ethernet (100 Mbps) interface could easily oversubscribe the 45-Mbps link. The carrier would need to use techniques such as traffic policing and traffic shaping to able to sell its customers tiered bandwidth. These techniques are The definitive guide tobe Enterprise and Carrier Metro Ethernet applications. discussed in Chapter 3, "Metro Ethernet Services," as part of a discussion about bandwidth parameters defined by the Metro Ethernet Forum (MEF). Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

EOS with Packet Switching Learn from the easy-to-read format that enables networking professionals of all levels to
understand the concepts The discussion thus far has addressed the ability to deliver a basic point-to-point leased-line or Gain from the experience of industry innovator and best-selling Cisco Press author, Internet-connectivity service. More-advanced VPN services can also be delivered over a Sam Halabi, author of Internet Routing Architectures SONET/SDH metro network that supports EOS. With a VPN service, the assumption is that different locations of the "same" customer exist in a metro area, and the customer wants to be Metro networks will locations emerge as the next area of growth the industry andswitching. will able to tie to these via a virtual network. This for type of networking service requires packet represent a major shift in how data services are offered to businesses and residential customers. Of course, if all the customer wants is a point-to-point service, no switching is required. The metro has always been a challenging environment for delivering data services because it has been built to handle stringent reliability and needs for voice. Carriers will have to Packet switching canthe be delivered using either ofavailability two methods: go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Centralized switching operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Local switching Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers andCentralized challenges carriers will face in transforming the metro to address data services. EOS with Switching Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers With centralized switching, a TDM circuit is provisioned from each building to the CO. All circuits to the delivery of metro data services. With a changing mix of transport technologies, the book are terminated in the CO, which is where the packet switching happens. Note that the standard then examines current and emerging trends, and delves into the role of virtual private networks SONET/SDH operation in unidirectional path switched rings (UPSRs) is to have active circuits and (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic protect circuits on the other side of the ring to achieve the 50-ms ring failure. So, in the metro engineering, and MPLS and Generalized MPLS (GMPLS). that has 50 buildings, 50 active STS-1s and 50 protect STS-1 circuits are provisioned. Also note that in case the XC does not support packet tagging or switching, 50 Ethernet interfaces need to be connected to the Ethernet switch at the CO. In Figure 2-10, customer A in sites 1 and 2 belongs to VPN A, while customer B in sites 1 and 2 belongs to VPN B.

Figure 2-10. EOS with Centralized Switching
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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

EOS with Local Switching
With local switching, packet switching occurs on each node in the ring. The difference here is The guide to Enterprise and Carrier Metro Ethernet applications. that definitive TDM circuits are no longer provisioned between the buildings and the CO but are instead provisioned around the ring. Each ADM in the building terminates circuits for both east and west, and packets get switched at the local switching function in the basement of the building, as Discover the latest developments in metro networking, Ethernet, and MPLS services and shown in Figure 2-11. In this case, SONET/SDH ring protection is not used. The metro carrier what they can do for your organization must rely on higher-level protection. In the case of L2 Ethernet, this means implementing standard spanning-tree mechanisms, such as the Spanning Tree Protocol (STP), or some other Learn from the easy-to-read format that enables networking professionals of all levels to proprietary mechanisms that the Ethernet switch vendor offers. For example, STP would block understand the concepts one side of the ring to prevent a broadcast storm. Also note in Figure 2-11 that in each ADM, a separate Ethernet interface is dedicated to innovator each TDMand circuit that gets Cisco terminated, unless Sam the Gain from the experience of industry best-selling Press author, ADM Halabi, itself has a packet-switching function to aggregate the traffic toward the building. If more author of Internet Routing Architectures bandwidth is needed for the building, VCAT can be used to aggregate more circuits while still making them look like a single Metro networks will emerge as pipe. the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Figure 2-11. EOS with Local Switching been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is size not image] only a technology shift, but also a shift in the [View full operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

A variation of local switching is to integrate the Ethernet switching function and the ADM/EOS function into one box, as shown in Figure 2-12.

Figure 2-12. A Variation of EOS with Local Switching

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 In this case, the TDM circuits are still terminated at each switch/ADM box on the ring. The benefit of this model is that it reduces the number of boxes deployed in the network; however, it blurs the line between the operation of data and TDM networks.

You probably realize by now why metro carriers that are used to SONET/SDH provisioning would like stay close to the same old circuit-provisioning model. The terms "spanning tree" and The to definitive guide to Enterprise and Carrier Metro Ethernet applications. "broadcast storms" give metro operators the jitters, because these are enterprise terms that sound very threatening for carriers that are bound to strict SLAs. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

EOS Interfaces in the Data Equipment Learn from the easy-to-read format that enables networking professionals of all levels to
understand the concepts So far, this chapter has discussed different scenarios for having an EOS interface within the Gain equipment. from the experience of industry innovator and in best-selling Press author, Sam of transport This section discusses the scenario which theCisco EOS interfaces are part Halabi, author of Internet Routing Architectures the data equipment rather than the transport equipment. In this model, the transport equipment does not have to deal with mapping the Ethernet frames carried in the SONET/SDH payload; the Metro networksequipment will emerge as the next area of growth for the networking industry and will data-switching does that instead. represent a major shift in how data services are offered to businesses and residential customers. metro has always been a data challenging environment for data services because it has The EOS interfaces inside the equipment, as shown indelivering Figure 2-13, are SONET/SDH been built with to handle the stringent reliability and availability needs for inside voice. Carriers will have to interfaces a mapping function that maps the EOS frames carried the SONET/SDH go through fundamental shifts The to equip the metro next-generation services demanded payload to an Ethernet frame. Ethernet frame for is in turn presented data to the switching logic by enterprise customers and consumers. is not only a technology shift, but also can a shift in the inside the data equipment. As in the caseThis of transport equipment, the EOS interface support operational and business model that allow the incumbent carriers to transform metro VCAT. The advantage of this model iswill that the switching function, the EOS function,the and the to offer enhanced services. VCAT functions data are all in the same box and are decoupled from the TDM box, which may already be installed in the network. This allows the data equipment to have better control over mapping Metro Ethernet from Cisco over Pressthe looks at the deployment of metro data services from a holistic the different data streams SONET/SDH circuits. With this model, multipoint-toview. It describes the current services metro, which isdelivered based on efficiently TDM technology, and discusses the multipoint switched Ethernet can be while leveraging the existing drivers SONET/SDH and challenges carriers will This facealso in transforming the the metro to address data services. legacy infrastructure. fits better with current operational model, in which transport and data are managed separately. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Figure 2-13. EOS and in the Data then examines current and emerging trends, delves into Equipment the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003

The previously ISBN: 1-58705-096-X mentioned EOS scenarios are bound to create a lot of debates and confusion in the industry. From a technology perspective, all options are viable, assuming the vendor Pages: 240 equipment is capable of delivering the services. From a business perspective, the ownership of the EOS interface determines who makes money on the sale: the data-switching vendors or the transport vendors. You will see numerous debates from both ends about where the EOS services and functions such as VCAT start and terminate. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Resilient Packet Ring
RPR also plays an important role in the development of data services in the metro. RPR is a new Media Access Control (MAC) protocol that is designed to optimize bandwidth management and to facilitate the deployment of data services over a ring network. The roots of RPR go back to the • Table of Contents point at which Cisco Systems adopted a proprietary Data Packet Transport (DPT) technology to • Index optimize packet rings for resiliency and bandwidth management. DPT found its way into the IEEE Metro Ethernet 802.17 workgroup, which led to the creation of an RPR standard that differs from the initial DPT approach. By Sam Halabi RPR has so far been a very attractive approach to multiple service operators (MSOs), such as Publisher: Cisco Press cable operators that are aggregating traffic from cable modem termination systems (CMTSs) in Date: October 01, 2003 the Pub metro. It remains to been seen whether RPR will be deployed by the incumbent carriers, ISBN: such as the 1-58705-096-X RBOCs and ILECs, that so far haven't been widely attracted to the RPR concept. The Pages: 240 why they lack interest is that they view RPR deployments as new deployments, primary reason compared to EOS deployments, which leverage existing infrastructure and are therefore more evolutionary. RPR is a new packet-ring technology that is deployed over dark fiber or wavelength division multiplexing (WDM) instead of the traditional SONET/SDH rings. RPR could be deployed as an overlay over existing SONET/SDH infrastructure; however, the complexity of overlaying logical RPR rings over SONET/SDH rings will probably not be too attractive to many The definitive guide to physical Enterprise and Carrier Metro Ethernet applications. operators. Although RPR and EOS solve different issues in the metro (EOS solves Ethernet service deployment, and RPR solves bandwidth efficiency on packet rings), both technologies will compete Discover for the the metro latest provider's developments mind in share. metro networking, Ethernet, and MPLS services and what they can do for your organization Figure 2-14 shows a typical RPR deployment with a cable operator. The CMTSs aggregate the traffic Learn coming from over the the easy-to-read coaxial cable format from that businesses enables and networking homes and professionals hand over of the all data levels portion to (assuming understand the cable the is concepts carrying voice/video as well) to the RPR router. Multiple RPR routers connect via an OC48 packet ring, and the traffic gets aggregated in the core hub, where Internet Gain from the experience of industry innovator and best-selling Cisco Press author, Sam connectivity is established. Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, with and delves the role of virtual private EOS networks RPR is somehow more commonly associated routersinto than with switches, whereas is (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic more commonly associated with switches than routers. The reason for these associations is that engineering, and MPLS and Generalized DPT historically has been deployed usingMPLS Cisco(GMPLS). IP routers for delivering routed IP services over a packet ring. While the IEEE 802.17 standards body would like to make RPR independent of Layer 2 (L2) switching or Layer 3 (L3) routing, the fact remains that RPR has so far been adopted for L3 services. Also, many routers lack the right functionality to deliver L2 services, which makes EOS more suitable for switches. Again, while the technologically savvy reader might argue that L2 or L3 could be delivered with either technology—and there are existing platforms that support

Figure 2-14. RPR Deployments

both L2 and L3 services—service provider adoption will be the determining factor in how each technology will most likely be used. In comparing RPR with traditional SONET/SDH rings, you will realize that RPR deployments have many advantages simply because RPR is a protocol built from the ground up to support data rings. The following sections discuss several features of RPR.
• Table of Contents

RPR Packet Add, Drop, and Forward • Index
Metro Ethernet

The RPR operation consists of three basic operations: add, drop, and forward. These operations BySam Halabi mimic the add/drop mechanisms that are used in traditional SONET networks, where circuits get added, dropped, and cross-connected inside a ring.
Publisher: Cisco Press Date: October 01,RPR 2003 has over a traditional Ethernet switched packet ring is that Ethernet ThePub advantage that ISBN: 1-58705-096-X 802.3 MAC operation processes packets at each node of the ring irrespective of whether the Pages: 240 packet destination is behind that node. In contrast, RPR 802.17 MAC forwards the traffic on the ring without doing any intermediary switching or buffering if the traffic does not belong to the node. This reduces the amount of work individual nodes have to do.

In the RPR operation shown in Figure 2-15, traffic that does not belong to a particular node is transited (forwarded) on the ring by the 802.17 MAC. In the Ethernet 802.3 MAC operation, the The definitive guide to Enterprise and Carrier Metro Ethernet applications. traffic is processed and buffered at each node for the switching function to determine the exit interface. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Figure 2-15. RPR Add, Drop, and Forward Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts [View full size image] Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book RPR's advantage over a SONET/SDH is that the packets coming theprivate ring share the then examines current and emerging ring trends, andall delves into the role of into virtual networks full-ring bandwidth, and the RPRnetworks mechanism manages the bandwidth to avoid (VPN), virtual private local area (VLAN), virtual private LAN allocation services (VPLS), traffic congestion and hot spots. InGeneralized a SONET/SDH ring, TDM time slots are allocated to each circuit, engineering, and MPLS and MPLS (GMPLS). and the bandwidth is removed from the ring whether there is traffic on that circuit or not.

RPR Resiliency

RPR offers ring protection in 50 ms, comparable with the traditional SONET/SDH protection. RPR fast protection with full-ring bandwidth utilization is probably one of the main assets that RPR has when compared to SONET/SDH and other packet-protection mechanisms. RPR protection is achieved in two ways: Ring wrapping— The ring is patched at the location of the fault.
• • Table of Contents Index Ring steering— In case of failure, the traffic is redirected (steered) at the source toward Metro the Ethernet working portion of the ring.
BySam Halabi

In general, the physical layer detects faults and signals that information to the MAC layer. If the failure is determined to be critical, each affected RPR node initiates a fail-over action for the Publisher: Cisco Press service flows it originates that are affected by the facility outage. The fail-over action is a simple Pub Date: of October 01, 2003 redirection the traffic from the failed path to the protection path. The process of alarm ISBN: 1-58705-096-X notification and redirecting traffic is completed within 50 ms of the outage.
Pages: 240

Figure 2-16 compares and contrasts RPR and SONET/SDH. In the SONET/SDH UPSR schemes, for example, 50-ms protection is achieved by having a working fiber and a standby protect fiber at all times. A sending node transmits on both fibers (east and west) at the same time, and a receiving node accepts traffic from only one side. In case of a fiber cut, recovery is done in less than 50 ms. In UPSRs, only 50 percent of the fiber capacity is used, because the other half is The definitive guide to Enterprise and Carrier Metro Ethernet applications. kept for failure mode. In RPR, both fiber rings—the outer ring and the inner ring—are used to utilize 100 percent of the ring capacity. In case of a failure, the ring wraps, isolating the failed portion. So, in the essence, effective bandwidth an RPR ring is twiceand as much a SONET/SDH Discover latest the developments in metro of networking, Ethernet, MPLSas services and ring because of the SONET/SDH protection. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to Figure 2-16. RPR Protection understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam [View full size image] Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers RPR Fairness to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks RPR implements a fairness algorithm to give everyvirtual node on the ring a services fair share of the traffic ring. RPR (VPN), virtual private local area networks (VLAN), private LAN (VPLS), uses access-control mechanisms to ensure fairness and to bound latency on the ring. The access engineering, and MPLS and Generalized MPLS (GMPLS). control can be broken into two types, which can be applied at the same time: Global access control— Controls access so that every node can get a fair share of the ring's global bandwidth.

Local access control— Gives the node additional ring access—that is, bandwidth beyond what was globally allocated—to take advantage of segments that are less-used. RPR uses the special reuse protocol (SRP), which is a concept used in rings to increase the ring's overall aggregate bandwidth. This is possible because multiple spans of the ring can be used simultaneously without having the traffic on one span affect the traffic on the other spans. If a node experiences congestion, it notifies the upstream nodes on the ring, which in turn adjust the transmit rate to relieve downstream congestion.
• Table of Contents • Index ring bandwidth fairness between RPR and L2 Ethernet rings. In the case of It helps to contrast
Metro Ethernetring an Ethernet

with L2 switching, there is no such thing as ring fairness, because the QoS decisions By Sam Halabi are local to each node, irrespective of what is on the ring. You can use rate-limiting techniques to prevent a set of customers who are coming in on one node from oversubscribing the Publisher: ring; however, it would be hard to have a global fairness mechanism without resorting to Cisco Press complicated QoS management software applications that would coordinate between all nodes. Pub Date: October 01, 2003 Figure ISBN: 2-171-58705-096-X shows three different scenarios for SONET/SDH UPSR, RPR, and L2 Ethernet rings. 240 In thePages: SONET/SDH case, if an STS-1 is allocated, the ring loses an STS-1 worth of bandwidth, irrespective of actual traffic. In the Ethernet case, traffic from A to C and from B to C might oversubscribe the capacity of the point-to-point link between switches SW2 and SW3. In the RPR case, the MAC entity on each node monitors the utilization on its immediate links and makes that information available to all nodes on the ring. Each node can then send more data or throttle back. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
[View full size image]

Figure 2-17. Ring Bandwidth

Ethernet Transport
So far, this book has addressed the reasoning behind adopting Ethernet as an access interface rather than a TDM interface. But as discussed in this section, Ethernet isn't limited to being an access technology. Many efforts have been made to extend Ethernet itself into the MAN as a • Table of Contents transport technology. Since the early 2000s, metro Ethernet deployments have taken many • Index some have proven to work, and others have not. When Ethernet is used as a shapes and forms; Metro Ethernet transport technology, the access network can be built in either ring or hub-and-spoke topologies. These are discussed next. By Sam Halabi
Publisher: Cisco Press

Gigabit Ethernet Hub-and-Spoke Configuration Pub Date: October 01, 2003
ISBN: 1-58705-096-X

In a Gigabit Ethernet hub-and-spoke configuration, Ethernet switches deployed in the basement Pages: 240 of buildings are dual-homed into the nearest point of presence (POP) or CO. Dedicated fiber, or dedicated wavelengths using WDM, is used for connectivity. Although this is the most expensive approach for metro access deployments because of the cost of fiber, some carriers consider it to be the better solution as far as survivability and scalability compared to deploying Ethernet in a ring topology (described in the next section). With the hub-and-spoke model, the bandwidth The definitive guide to Enterprise and Carrier Metro Ethernet applications. dedicated to each building can scale, because the full fiber is dedicated to the building. Protection schemes can be achieved via mechanisms such as link aggregation 802.3ad or dual homing. With link two fibers are aggregated into a biggerand pipe that services connectsand to the Discover the aggregation, latest developments in metro networking, Ethernet, MPLS CO. Traffic is load-balanced between the two fibers, and if one fiber is damaged, the other what they can do for your organization absorbs the full load. This, of course, assumes that the two fibers are run into two different conduits to the CO for better protection. shown in Figure 2-18 for connection Learn from the easy-to-read formatThis thatscenario enables is networking professionals ofthe all levels to between building the 1 and the CO. understand concepts Gain from the experience of2-18. industry innovator and best-selling Cisco Press author, Sam Figure Ethernet Hub and Spoke Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Another approach is to dual-home the fiber into different switches at the CO, as shown in Figure 2-18 for buildings 2 and 3. Although this prevents a single point of failure on the switching side, it creates more complexities, because STP must be run between the buildings and the CO,

causing traffic on one of the dual-homed links to be blocked.

Gigabit Ethernet Rings
Many fiber deployments in the metro are laid in ring configurations. Consequently, ring topologies are the most natural to implement and result in cost savings. However, the situation • Table of Contents differs depending on whether you are dealing with U.S. carriers or international carriers, • Index incumbents, or greenfields. Ring deployments could be extremely cost-effective for one carrier Metro but a Ethernet nonissue for another. For existing fiber laid out in a ring topology, Gigabit Ethernet rings are a series By Sam Halabi of point-to-point connections between the switches in the building basements and the CO, as shown in Figure 2-19. As simple as they might look, Gigabit Ethernet rings may create many issues for the operators because of protection and bandwidth limitations. First of Publisher: Cisco Press all, ring capacity could be a major issue. Gigabit Ethernet rings have only 1 GB of capacity to Pub Date: October 01, 2003 share between all buildings, and some of that capacity is not available because spanning tree ISBN: 1-58705-096-X blocks portions of the ring to prevent loops.
Pages: 240

Figure 2-19. Gigabit Ethernet Rings

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. With an Ethernet L2 switched operation, the ring itself becomes a collection of point-to-point Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic links. Even without a fiber cut, spanning tree blocks portions of the ring to prevent broadcast view. It describes the current metro, which is based on TDM technology, and discusses the storms caused by loops (see Part A of Figure 2-20). Broadcast storms occur, for example, when drivers and challenges carriers will face in transforming the metro to address data services. a packet with an unknown destination reaches a node. The node floods the packet over the ring according to standard bridging operation as defined in 802.3d. If there is athat loophas in the Metro Ethernet discusses the adoption of metro Ethernet services and how led network carriers (in this case, the ring), the packet could end up being received and forwarded by the node to the delivery of metro data services. With a changing mix of transport technologies,same the book over and over. The spanning-tree algorithm uses control packets called bridge protocol data then examines current and emerging trends, and delves into the role of virtual private networks units (BPDUs) to discover block (VLAN), them. Spanning tree normally takes (VPLS), between 30 and (VPN), virtual private localloops area and networks virtual private LAN services traffic 60 seconds to converge. The new 802.1W Rapid Spanning Tree allows faster convergence but engineering, and MPLS and Generalized MPLS (GMPLS). still doesn't come close to 50 ms. Many proprietary algorithms have been introduced to achieve ring convergence in less than 1 second, which many operators view as good enough for data services and even for Voice over IP (VoIP) services. However, because L2 switching cannot operate in a loop environment, many of these algorithms still need to block redundant paths in the ring to prevent broadcast storms, and are not considered as reliable as RPR or SONET/SDH protection mechanisms that are more carrier-class. When a fiber cut occurs, spanning tree

readjusts, and the new path between the different nodes is established, as shown in Part B of Figure 2-20.

Figure 2-20. Gigabit Ethernet Rings—Spanning Tree

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Although 10-Gigabit Ethernet rings wouldthat alleviate the networking congestion professionals issues, initial of solutions for 10Learn from the easy-to-read format enables all levels to GE switches are cost-prohibitive. Initial equipment with 10-GE interfaces was designed for core understand the concepts networks rather than building access. As 10-GE solutions mature and their prices are reduced to fit the building 10-GE rings will become a viable Gain fromaccess, the experience of industry innovator and solution. best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Other methods, such as deploying WDM, could be used to add capacity on the ring. It is debatable whether methods are cost-effective for prime-time deployments, because they Metro networks willsuch emerge as the next area of growth for the networking industry and will increase the operational overhead of deploying access represent a major shift in how data services arethe offered to ring. businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
So far, you have read about different technologies that can be used for physical metro connectivity. Ethernet over SONET, RPRs, and Ethernet transport are all viable methods to deploy a metro Ethernet service. Ethernet over SONET presents a viable solution for deploying • Table of Contents Ethernet services over an existing installed base. You have seen how virtual concatenation allows • Index better efficiency and bandwidth granularity when mapping Ethernet pipes over SONET/SDH Metro rings.Ethernet RPR is a packet-ring technology that is attracting much interest from MSOs because it solves many of the restoration and bandwidth inefficiencies that exist in SONET/SDH rings. By Sam Halabi Ethernet as a transport technology is also a simple and efficient way to deploy Ethernet services; however, by itself, this solution inherits many of the deficiencies of L2 switched Ethernet Publisher: Cisco Press networks.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Much functionality still needs to be offered on top of metro equipment to deliver revenuePages: services 240 generating such as Internet connectivity and VPN services. Ethernet, for example, has always been used in a single-customer environment, such as an enterprise network. It is now moving to a multicustomer environment in which the same equipment delivers services to different customers over a shared carrier network. Issues of virtualization of the service and service scalability become major issues. Ethernet over MPLS (EoMPLS) is becoming a viable solution for deploying metro services. The MPLS control plane delivers most of The definitive guide toscalable Enterprise and Ethernet Carrier Metro Ethernet applications. the functionality that is lacking in Ethernet switched networks as far as scalability and resiliency. Chapter 3 discusses metro Ethernet services and Layer 2 switching, in preparation for Chapter 4, which Discover discusses the delivering latest developments Ethernet over in hybrid metro Ethernet networking, andEthernet, IP/MPLS networks. and MPLS services and what they can do for your organization

Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 3. Metro Ethernet Services
This chapter covers the following topics:
• •

L2 Switching Basics
Index

Table of Contents

Metro Metro Ethernet Ethernet BySam Halabi

Services Concepts

Example of an L2 Metro Ethernet Service
Publisher: Cisco Press Pub Date: October 01, 2003

Challenges with All-Ethernet Metro Networks

ISBN: 1-58705-096-X As discussed in Chapter 1, "Introduction to Data in the Metro," Ethernet services can take either of twoPages: forms: 240a retail service that competes with traditional T1/E1 private-line services, or a wholesale service where a carrier sells a big Ethernet transport pipe to another, smaller service provider. In either case, multiple customers share the same metro infrastructure and equipment. For TDM deployments, sharing the infrastructure is a nonissue, because the services are limited to selling transport pipes, and each customer is allocated a circuit that isolates its traffic from other customers. The customer gets well-defined SLAs, mainly dictated by the circuit that is The definitive guide to Enterprise and Carrier Metro Ethernet applications. purchased.

WhenDiscover packet multiplexing and switching applied, such asEthernet, in the cases switched EOS, the latest developments in are metro networking, andof MPLS services and Ethernet Transport, and RPR, things change. Packets from different customers are multiplexed what they can do for your organization over the same pipe, and the bandwidth is shared. No physical boundaries separate one customer's from another's, only logical Separation of customer and Learn traffic from the easy-to-read format that boundaries. enables networking professionals of traffic all levels to packet queuing techniques have to be used to ensure QoS. Multiple functions have to be wellunderstand the concepts defined to offer a service: Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures How to identify different customers' traffic over a shared pipe or shared network Metro networks will emerge as the next area of growth for the networking industry and will How to identify and the service are given to a particular customer represent a major shift in enforce how data services offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has certain bandwidth to a and specific customer been How built to to allocate handle the stringent reliability availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded How to "transparently" move customers' traffic between different locations, such as in the by enterprise customers and consumers. This is not only a technology shift, but also a shift in the case of transparent LAN services operational and business model that will allow the incumbent carriers to transform the metro to offer How enhanced data services. to scale the number of customers MetroHow Ethernet froma Cisco Press looks the deployment of metro data services from a holistic to deploy VPN service that at offers any-to-any connectivity for the same customer view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro toto address data you services. This chapter starts by discussing the basics of L2 Ethernet switching familiarize with Ethernet-switching concepts. Then it discusses the different metro Ethernet service concepts as Metro Ethernet discusses the adoption of (MEF). metro Ethernet services and how that has led carriers introduced by the Metro Ethernet Forum to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

L2 Switching Basics
L2 switching allows packets to be switched in the network based on their Media Access Control (MAC) address. When a packet arrives at the switch, the switch checks the packet's destination MAC address and, if known, sends the packet to the output port from which it learned the • Table of Contents destination MAC.
• Index
Metro Ethernet The two fundamental elements in Ethernet L2 switching are the MAC address and the virtual LAN (VLAN). In BySam Halabi the same way that IP routing references stations on the networks via an L3 IP address, Ethernet L2 switching references end stations via the MAC address. However, unlike IP, in which IP addresses are assigned by administrators and can be reused in different private Publisher: Cisco Press networks, MAC addresses are supposed to be unique, because they are indicative of the Pub Date: October 01, 2003 hardware itself. Thus, MAC addresses should not be assigned by the network administrator. (Of ISBN: 1-58705-096-X course, in some cases the MAC addresses can be overwritten or duplicated, but this is not the Pages: 240 norm.)

Ethernet is a broadcast medium. Without the concept of VLANs, a broadcast sent by a station on the LAN is sent to all physical segments of the switched LAN. The VLAN concept allows the segmentation of the LAN into logical entities, and traffic is localized within those logical entities. For university campusand can Carrier be allocated VLANs—one dedicated for faculty, The example, definitive a guide to Enterprise Metromultiple Ethernet applications. one dedicated for students, and the third dedicated for visitors. Broadcast traffic within each of these VLANs is isolated to that VLAN. Discover the latest developments in metro networking, Ethernet, and MPLS services and Figure 3-1 they shows the concept oforganization an Ethernet LAN using a hub (Part A) and an Ethernet switch what can do for your (Part B). With an Ethernet hub, all stations on the LAN share the same physical segment. A 10MbpsLearn hub, for example, allows broadcast between the stations shareto the from the easy-to-read format and that unicast enablestraffic networking professionals ofthat all levels 10-Mbps bandwidth. The switched LAN on the right allows each segment a 100-Mbps connection understand the concepts (for this example), and it segments the LAN into two logical domains, VLAN 10 and VLAN 20. The concept Gain of from VLANs the is experience independent of of industry the stations innovator themselves. and best-selling The VLAN Cisco is an Press allocation author, bySam the switch. Halabi, In this author example, of Internet ports 1Routing and 2 are Architectures allocated to VLAN 10, while ports 3 and 4 are allocated to VLAN 20. When stations A1 and A2 send traffic, the switch tags the traffic with the Metro assigned networksto will emerge as the area of growth for the networking industry andnumber. will VLAN the interface and next makes the switching decisions based on that VLAN represent shift in how a data services are offered to businesses andVLANs. residential customers. The result a ismajor that traffic within VLAN is isolated from traffic within other The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Figure 3-1. Ethernet MACs and VLANs go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Ethernet switching includes the following basic concepts: Discover the latest developments in metro networking, Ethernet, and MPLS services and MAC learning what they can do for your organization Flooding Learn from the easy-to-read format that enables networking professionals of all levels to Using broadcast and multicast understand the concepts Expanding the experience network with trunks innovator and best-selling Cisco Press author, Sam Gain from the of industry Halabi, author of Internet Routing Architectures VLAN tagging Metro networks will emerge as the next area of growth for the networking industry and will The need for the Spanning Tree Protocol (STP) represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded MAC Learning by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to MAC learning allows the Ethernet switch to learn the MAC addresses of the stations in the offer enhanced data services. network to identify on which port to send the traffic. LAN switches normally keep a MAC learning table a bridge table) and a VLAN table. The MAC learning tabledata associates the MACs/VLANs Metro(or Ethernet from Cisco Press looks at the deployment of metro services from a holistic with a given port, and the VLAN table associates the port with a VLAN. In Figure 3-1, Part view. It describes the current metro, which is based on TDM technology, and discusses theB, the switch has learned the MAC addresses of stations A1, A2, B1, and B2 on ports 1, 2, 4, and 3, drivers and challenges carriers will face in transforming the metro to address data services. respectively. It also shows that ports 1 and 2 are associated with VLAN 10 and ports 3 and 4 are associated with discusses VLAN 20. the adoption of metro Ethernet services and how that has led carriers Metro Ethernet to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Flooding engineering, and MPLS and Generalized MPLS (GMPLS). If the switch receives a packet with a destination MAC address that does not exist in the bridge table, the switch sends that packet over all its interfaces that belong to the same VLAN assigned to the interface where the packet came in from. The switch does not flood the frame out the port that generated the original frame. This mechanism is called flooding. It allows the fast delivery of packets to their destinations even before all MAC addresses have been learned by all switches in

the network. The drawback of flooding is that it consumes switch and network resources that otherwise wouldn't have been used if the switch had already learned which port to send the packet to. VLANs minimize the effect of flooding because they concentrate the flooding within a particular VLAN. The switch uses the VLAN table to map the VLAN number of the port on which the packet arrived to a list of ports that the packet is flooded on.
• • Table of Contents Index

Using Broadcast and Multicast Metro Ethernet
BySam Halabi

Broadcast is used to enable clients to discover resources that are advertised by servers. When a server advertises its services to its clients, it sends broadcast messages to MAC address FFFF Publisher: Cisco Press FFFF FFFF, which means "all stations." End clients listen to the broadcast and pick up only the Pub Date: October 01, 2003 broadcasts they are interested in, to minimize their CPU usage. With multicast, a subset of ISBN: 1-58705-096-X broadcast, a station sends traffic only to a group of stations and not to all stations. Broadcast Pages: 240addresses are treated as unknown destinations and are flooded over all ports and multicast within a VLAN. Some higher-layer protocols such IGMP snooping help mitigate the flooding of IP multicast packets over an L2 switched network by identifying which set of ports a packet is to be flooded on. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Expanding the Network with Trunks
Discover the latest developments in metro networking, Ethernet, and MPLS services and So far you they havecan seen the a single L2 switch. An L2 Ethernet-switched network would what do forcase yourof organization consist of many interconnected switches with trunk ports. The trunk ports are similar to the access ports used to easy-to-read connect end stations; however, they have theprofessionals added task of carrying traffic Learn from the format that enables networking of all levels to coming in from many VLANs in the network. This scenario is shown in Figure 3-2. Trunk ports understand the concepts could connect Ethernet switches built by different vendors—hence the need for standardization for VLAN Gain tagging from the mechanisms. experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book In Figure 3-2, switches and SW3 trends, have assigned access port with 10 and access port then examines current SW1 and emerging and delves into the 1 role of VLAN virtual private networks 2 with VLAN 20. Port 3 is a area trunk port that(VLAN), is used virtual to connect to other switches(VPLS), in the network. (VPN), virtual private local networks private LAN services traffic Note that SW2 in MPLS the middle has no access ports and is used only to interconnect trunk ports. engineering, and and Generalized MPLS (GMPLS). You can see that the simplicity of switched Ethernet becomes extremely complex because VLAN assignments need to be tracked inside the network to allow the right traffic to be switched on the right ports. In Frame Relay, ATM, and MPLS, similar complexities do exist, and signaling is introduced to solve the network connectivity issues. Ethernet has not defined a signaling protocol. The only mechanisms that Ethernet networks have are third-party applications that surf

Figure 3-2. Trunk Ports

the network and make it easier to do some VLAN allocations. While these mechanisms work in small enterprise environments, they immediately became showstoppers in larger enterprise deployments and carrier networks. Chapter 4 discusses LDP as a signaling mechanism for delivering Ethernet services. Chapter 7 discusses RSVP-TE and its use in relation to scaling the Ethernet services.

• Table of Contents VLAN Tagging •
Metro Ethernet IEEE 802.1Q

Index

defines how an Ethernet frame gets tagged with a VLAN ID. The VLAN ID is assigned by the switch and not the end station. The switch assigns a VLAN number to a port, and By Sam Halabi every packet received on that port gets allocated that VLAN ID. The Ethernet switches switch packets between the same VLANs. Traffic between different VLANs is sent to a routing function Publisher: Cisco Press within the switch itself (if the switch supports L3 forwarding) or an external router. Figure 3-3 Pub Date: October 01, 2003 shows how the VLAN tags get inserted inside the untagged VLAN packet.
ISBN: 1-58705-096-X Pages: 240

Figure 3-3. VLAN Tagged Packet

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will The untagged Ethernet of the destination MAC addressand andresidential source MAC address, represent a major shift packet in how consists data services are offered to businesses customers. a Type field, and the data. 802.1Q tag header gets for inserted between source MAC it has The metro has always beenThe a challenging environment delivering datathe services because address and Type field. It consists of a 2-byte Type field needs and a for 2-byte Tag Control Info field. been built to the handle the stringent reliability and availability voice. Carriers will have to The 2-byte Type field is set to 0X8100 indicate tagged packet. The 2-byte Tag go through fundamental shifts to equipto the metro an for 802.1Q next-generation data services demanded Control Info field consists of the 3 leftmost bits 802.1P priority and thea12 by enterprise customers and consumers. This isindicating not only athe technology shift, but also shift in the rightmost bits indicating VLAN tag ID. The 802.1P field gives the Ethernet packet up to eight operational and business the model that will allow the incumbent carriers to transform the metro to different priority levels that can be used to offer different levels of service within the network. offer enhanced data services. The 12-bit VLAN ID field allows the assignment of up to 4096 (212 ) VLAN numbers to distinguish Metro Ethernet from Cisco packets. Press looks at the deployment of metro data services from a holistic the different VLAN tagged view. It describes the current metro, which is based on TDM technology, and discusses the Metro Ethernet applications require extensions to L2 switching thatto are not defined in the drivers and challenges carriers will face in transforming the metro address data services. standards. An example is the ability to do VLAN stacking—that is, to do multiple VLAN tagging to Metro Ethernet discusses adoption metro Ethernet services and how that led carriers the same Ethernet packet the and create a of stack of VLAN IDs. Different entities can has do L2 switching to the delivery of metro data services. With a changing mix of transport technologies, the on the different levels of the VLAN stack. Cisco Systems calls this concept Q-in-Q, short forbook then examines current and emerging trends, 802.1Q-in-802.1Q, as shown in Figure 3-4. and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS3-4. (GMPLS). Figure Q-in-Q

• Table of Contents As shown, an already tagged frame can be tagged again to create a hierarchy. The simplicity of • Index Ethernet, the lack of standardization for many such extensions, the reliance on STP, and the
Metro Ethernet explosion of MAC

addresses contribute to the lack of confidence of many providers in deploying a large-scale, BySam Halabi all-Ethernet network. VLAN tag support is discussed more in the section "VLAN Tag Support Attribute."
Publisher: Cisco Press Pub Date: October 01, 2003

The Need for the Spanning Tree Protocol Pages: 240
L2 Ethernet-switched networks work on the basis of MAC address learning and flooding. If multiple paths exist to the same destination, and the packet has an unknown destination, packet flooding might cause the packet to be sent back to the original switch that put it on the network, causing a broadcast storm. STP prevents loops in the network by blocking redundant paths and The definitive guide to Enterprise and Carrier Metro Ethernet applications. ensuring that only one active path exists between every two switches in the network. STP uses bridge protocol data units (BPDUs), which are control packets that travel in the network and identify which path, and developments hence ports, need to benetworking, blocked. Discover the latest in metro Ethernet, and MPLS services and what they can do for your organization The next section covers in detail the Ethernet services concepts as defined by the Metro Ethernet Forum. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

ISBN: 1-58705-096-X

Metro Ethernet Services Concepts
The Metro Ethernet Forum is a nonprofit organization that has been active in defining the scope, concepts, and terminology for deploying Ethernet services in the metro. Other standards bodies, such as the Internet Engineering Task Force (IETF), have also defined ways of scaling Ethernet • Table the of Contents services through use of MPLS. While the terminologies might differ slightly, the concepts and • Index directions taken by these different bodies are converging.
Metro Ethernet

For Ethernet BySam Halabi services, the MEF defines a set of attributes and parameters that describe the service and SLA that are set between the metro carrier and its customer.
Publisher: Cisco Press Pub Date: October 01, 2003

Ethernet Service Definition ISBN: 1-58705-096-X
Pages: 240

The MEF defines a User-to-Network Interface (UNI) and Ethernet Virtual Connection (EVC). The UNI is a standard Ethernet interface that is the point of demarcation between the customer equipment and the service provider's metro Ethernet network. The EVC is defined by the MEF as "an association of two or more UNIs." In other words, the EVC The definitive guide to connects Enterprise and Carrier Metro(MP2MP) Ethernet sites, applications. is a logical tunnel that two (P2P) or more enabling the transfer of Ethernet frames between them. The EVC also acts as a separation between the different customers and provides data privacy and security similar to Frame Relay or ATM permanent Discover the latest developments in metro networking, Ethernet, and MPLS services and virtual circuits (PVCs). what they can do for your organization The MEF has defined two Ethernet service types: Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Ethernet Line Service (ELS)— This is basically a point-to-point (P2P) Ethernet service. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author Internet Routing Architectures Ethernet LAN of Service (E-LAN)— This is a multipoint-to-multipoint (MP2MP) Ethernet service. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data a services are offeredtwo to businesses and residential customers. The Ethernet Line Service provides P2P EVC between subscribers, similar to a Frame Relay The metro has always been a challenging environment for delivering data services because it has or private leased-line service (see Figure 3-5). been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Figure 3-5. Ethernet Concepts by enterprise customers and consumers. This is notService only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Figure 3-5 also illustrates the E-LAN, which provides multipoint connectivity between multiple subscribers in exactly the same an Ethernet-switched network. An E-LAN service Metro Ethernet from Cisco Pressmanner looks atas the deployment of metro data services from a holistic offers the most flexibility in providing a VPN service because one EVC touches all sites. a new view. It describes the current metro, which is based on TDM technology, and discusses If the site is added to the VPN, the new site participates in the EVC and has automatic connectivity drivers and challenges carriers will face in transforming the metro to address data services. to all other sites. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging and trends, and delves into the role of virtual private networks Ethernet Service Attributes Parameters (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). The MEF has developed an Ethernet services framework to help subscribers and service providers have a common nomenclature when talking about the different service types and their attributes. For each of the two service types, ELS and E-LAN, the MEF has defined the following service attributes and their corresponding parameters that define the capabilities of the service type:

Ethernet physical interface attribute Traffic parameters Performance parameters Class of service parameters
• •

ServiceIndex frame delivery attribute VLAN tag support attribute Service multiplexing attribute
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Security filters attribute Pages: 240

Table of Contents

Metro Ethernet BySam Halabi

Bundling attribute

Ethernet Physical Interface Attribute
The Ethernet physical interface attribute has the following parameters: The definitive guide to Enterprise and Carrier Metro Ethernet applications. Physical medium— Defines the physical medium per the IEEE 802.3 standard. Examples Discover the latest developments in metro networking, Ethernet, and MPLS services and are 10BASE-T, 100BASE-T, and 1000BASE-X. what they can do for your organization Speed— Defines the Ethernet speed: 10 Mbps, 100 Mbps, 1 Gbps, or 10 Gbps. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Mode— Indicates support for full duplex or half duplex and support for autospeed negotiation between Ethernet ports. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing MAC layer— Specifies which MAC Architectures layer is supported as specified in the 802.3-2002 standard. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Traffic Parameters been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded The MEF has defined a set of consumers. bandwidth profiles thatonly can a be applied at shift, the UNI to an EVC. by enterprise customers and This is not technology butor also a shift inA the bandwidth is a limit on the rate at allow which Ethernet frames can traverse the UNI the to operationalprofile and business model that will the incumbent carriers to transform theor metro EVC. Administering bandwidth profiles can be a tricky business. For P2P connections where offer enhanced datathe services. there is a single EVC between two sites, it is easy to calculate a bandwidth profile coming in and Metro out of Ethernet the pipe. from However, Ciscofor Press thelooks casesat where the deployment a multipoint of service metro is data delivered services and from there a holistic is the view. It describes possibility of having the multiple current EVCs metro, onwhich the same is based physical on TDM interface, technology, it becomes and discusses difficult to the drivers and determine the challenges bandwidth carriers profile will of face an EVC. in transforming In such cases, the limiting metro to the address bandwidth dataprofile services. per UNI might be more practical. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the The Bandwidth delivery of Profile metro service data services. attributes With are a as changing follows: mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Ingress and and MPLS egress bandwidth profile per (GMPLS). UNI engineering, and Generalized MPLS Ingress and egress bandwidth profile per EVC Ingress and egress bandwidth profile per CoS identifier Ingress bandwidth profile per destination UNI per EVC

Egress bandwidth profile per source UNI per EVC The Bandwidth Profile service attributes consist of the following traffic parameters: CIR (Committed Information Rate)— This is the minimum guaranteed throughput that the network must deliver for the service under normal operating conditions. A service can supportTable a CIR VLAN on the UNI interface; however, the sum of all CIRs should not • of per Contents exceed the physical port speed. The CIR has an additional parameter associated with it • Index called the Committed Burst Size (CBS). The CBS is the size up to which subscriber traffic is Metro Ethernet allowed to burst in profile and not be discarded or shaped. The in-profile frames are those BySam Halabi that meet the CIR and CBS parameters. The CBS may be specified in KB or MB. If, for example, a subscriber is allocated a 3-Mbps CIR and a 500-KB CBS, the subscriber is Publisher: Cisco Press guaranteed a minimum of 3 Mbps and can burst up to 500 KB of traffic and still remain Pub Date: October 01,limits. 2003 within the SLA If the traffic bursts above 500 KB, the traffic may be dropped or delayed. ISBN: 1-58705-096-X PIR (Peak Information Rate)— The PIR specifies the rate above the CIR at which traffic is allowed into the network and that may get delivered if the network is not congested. The PIR has an additional parameter associated with it called the Maximum Burst Size (MBS). The MBS is the size up to which the traffic is allowed to burst without being discarded. The MBS can be specified in KB or MB, similar to CBS. A sample service may provide a 3-Mbps The definitive guide to Enterprise and and Carrier Metro Ethernet applications. CIR, 500-KB CBS, 10-Mbps PIR, 1-MB MBS. In this case, the following behavior occurs: -Traffic is less than or equal to CIR (3 Mbps)— Traffic is in profile with a guaranteed Discover the latest developments in metro networking, Ethernet, and MPLS services and delivery. Traffic is also in profile if it bursts to CBS (500 KB) and may be dropped or what they can do for your organization delayed if it bursts beyond 500 KB. Learn from the easy-to-read format that enables networking professionals of all levels to -Traffic is more than CIR (3 Mbps) and less than PIR (10 Mbps)— Traffic is out of understand the concepts profile. It may get delivered if the network is not congested and the burst size is less than the MBS (1 MB). of industry innovator and best-selling Cisco Press author, Sam Gain from experience Halabi, author of Internet Routing Architectures -Traffic is more than PIR (10 Mbps)— Traffic is discarded. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Performance Parameters go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. is not only a technologyby shift, also a shift in the The performance parameters indicate theThis service quality experienced thebut subscriber. They operational and business model that will allow the incumbent carriers to transform the metro to consist of the following: offer enhanced data services. MetroAvailability Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Delay MetroJitter Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Loss then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
Pages: 240

Availability
Availability is specified by the following service attributes:

UNI Service Activation Time— Specifies the time from when the new or modified service order is placed to the time service is activated and usable. Remember that the main value proposition that an Ethernet service claims is the ability to cut down the service activation time to hours versus months with respect to the traditional telco model. UNI Mean Time to Restore (MTTR)— Specifies the time it takes from when the UNI is unavailable to when it is restored. Unavailability can be caused by a failure such as a fiber cut.
Table of Contents

• •

Index Activation Time— Specifies the time from when a new or modified service EVC Service placed to when the service is activated and usable. The EVC service activation time BySambegins Halabi when all UNIs are activated. For a multipoint EVC, for example, the service is considered active when all UNIs are active and operational.
Metro order Ethernet is Publisher: Cisco Press

Pub Date: October 01, 2003

EVC Availability— Specifies how often the subscriber's EVC meets or exceeds the delay, loss, and jitter service performance over the same measurement interval. If an EVC does ISBN: 1-58705-096-X not meet the performance criteria, it is considered unavailable.
Pages: 240

EVC (MTTR)— Specifies the time from when the EVC is unavailable to when it becomes available again. Many restoration mechanisms can be used on the physical layer (L1), the MAC layer (L2), or the network layer (L3). The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Delay
Discover the latest developments in metro networking, Ethernet, and MPLS services and Delay is a critical parameter that significantly impacts the quality of service (QoS) for real-time what they can do for your organization applications. Delay has traditionally been specified in one direction as one-way delay or end-toend delay. delay between two format sites inthat the enables metro isnetworking an accumulation of delays, Learn The from the easy-to-read professionals of starting all levelsfrom to one UNI at one end, going through the metro network, and going through the UNI on the other understand the concepts end. The delay at the UNI is affected by the line rate at the UNI connection and the supported Ethernet frame For example, a UNI connection 10 Mbps and 1518-byte frame size Gain from size. the experience of industry innovator with and best-selling Cisco Press author, Sam would cause 1.2 milliseconds (ms) of transmission delay (1518 * 8 / 106). Halabi, author of Internet Routing Architectures The metro network introduces additional delays based onnetworking the network backbone speed Metro networks will itself emerge as the next area of growth for the industry and will and level of congestion. The delay performance is defined by the 95th percentile (95 percent) of the represent a major shift in how data services are offered to businesses and residential customers. delay of successfully delivered egress frames over a time interval. For example, a delay of ms The metro has always been a challenging environment for delivering data services because15 it has over 24 hours means that over a period of 24 hours, 95 percent of the "delivered" frames had been built to handle the stringent reliability and availability needs for voice. Carriers will have a to one-way delay of less than or equal to 15 ms. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the The delay parameter is used in the following attributes: operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Ingress and egress bandwidth profile per CoS identifier (UNI service attribute) Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view.Class It describes the(EVC current metro, which is based on TDM technology, and discusses the of service service attribute) drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Jitter to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), Jitter isvirtual another private parameter local area that affects networks the (VLAN), service virtual quality. private Jitter is LAN also services known (VPLS), as delaytraffic engineering, variation. Jitter and has MPLS a very andadverse Generalized effect MPLS on real-time (GMPLS). applications such as IP telephony. The jitter parameter is used in the following service attributes: Ingress and egress bandwidth profile per CoS identifier (UNI service attribute) Class of service (EVC service attribute)

Loss
Loss indicates the percentage of Ethernet frames that are in-profile and that are not reliably delivered between UNIs over a time interval. On a P2P EVC, for example, if 100 frames have been sent from a UNI on one end and 90 frames that are in profile have been received on the • Table ofwould Contents other end, the loss be (100 – 90) / 100 = 10%. Loss can have adverse effects, depending on the application. • Index Applications such as e-mail and HTTP web browser requests can tolerate more Ethernet Metro loss than VoIP, for example. The loss parameter is used in the following attributes:
BySam Halabi

Ingress and egress bandwidth profile per CoS identifier (UNI service attribute)
Publisher: Cisco Press

Class service (EVC Pub Date: of October 01, 2003
ISBN: 1-58705-096-X Pages: 240

service attribute)

Class of Service Parameters
Class of service (CoS) parameters can be defined for metro Ethernet subscribers based on various CoS identifiers, such as the following: The definitive guide to Enterprise and Carrier Metro Ethernet applications. Physical port— This is the simplest form of QoS that applies to the physical port of the UNI connection. All developments traffic that enters and exits the portEthernet, receives the Discover the latest in metro networking, andsame MPLSCoS. services and what they can do for your organization Source/destination MAC addresses— This type of classification is used to give different types service based on combinations of source networking and destination MAC addresses. While Learn of from the easy-to-read format that enables professionals of all levels tothis model is very flexible, it is difficult to administer, depending on the service itself. If the understand the concepts customer premises equipment (CPE) at the ends of the connections are Layer 2 switches that part of a LAN-to-LAN service, hundreds or thousands ofCisco MAC addresses might have Gain are from the experience of industry innovator and best-selling Press author, Sam to be monitored. the other hand, if the CPEs are routers, the MAC addresses that are Halabi, author of On Internet Routing Architectures monitored are those of the router interfaces themselves. Hence, the MAC addresses are Metro networks will emerge as the next area of growth for the networking industry and will much more manageable. represent a major shift in how data services are offered to businesses and residential customers. VLANhas ID— This is a very practical way of assigning if the subscriber has because different it has The metro always been a challenging environment forCoS delivering data services on the the physical port reliability where a service is definedneeds by a VLAN ID (these would theto been services built to handle stringent and availability for voice. Carriers will be have carrier-assigned VLANs). go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the 802.1p value— Themodel 802.1p field allows to assign up to different levels of operational and business that will allowthe thecarrier incumbent carriers to eight transform the metro to theservices. customer traffic. Ethernet switches use this field to specify some basic offer priorities enhancedto data forwarding priorities, such as that frames with priority number 7 get forwarded ahead of with priority number 6, and on. This is one that services can be used to Metroframes Ethernet from Cisco Press looks at so the deployment ofmethod metro data from a holistic VoIP traffic and regular traffic or between high-priority and bestview.differentiate It describes between the current metro, which is based on TDM technology, and discusses the effort In all practicality, service providers are unlikely exceed two orservices. three levels drivers andtraffic. challenges carriers will face in transforming the metro to address data of priority, for the sake of manageability. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Diffserv/IP ToS—data The services. IP ToS field is a 3-bit field mix inside the IP packet that is used to to the delivery of metro With changing of transport technologies, the book provide eight different classes oftrends, serviceand known as IP precedence. field is similar to the then examines current and emerging delves into the role of This virtual private networks 802.1p field if used for basic forwarding priorities; however, it is services located inside the IP (VPN), virtual private local area networks (VLAN), virtual private LAN (VPLS), traffic header rather than theGeneralized Ethernet 802.1Q header. Diffserv has defined a more engineering, and MPLS and MPLStag (GMPLS). sophisticated CoS scheme than the simple forwarding priority scheme defined by ToS. Diffserv allows for 64 different CoS values, called Diffserv codepoints (DSCPs). Diffserv includes different per-hop behaviors (PHBs), such as Expedited Forwarding (EF) for a low delay, low-loss service, four classes of Assured Forwarding (AF) for bursty real-time and non-real-time services, Class Selector (CS) for some backward compatibility with IP ToS,

and Default Forwarding (DF) for best-effort services. Although Diffserv gives much more flexibility to configure CoS parameters, service providers are still constrained with the issue of manageability. This is similar to the airline QoS model. Although there are so many ways to arrange seats and who sits where and so many types of food service and luggage service to offer travelers, airlines can manage at most only three or four levels of service, such as economy, economy plus, business class, and first class. Beyond that, the overhead of maintaining these services and the SLAs Table of Contents associated with them becomes cost-prohibitive.
Index

• •

Metro Ethernet BySam Halabi

Service Frame Delivery Attribute
Publisher: Cisco Press Because the metro network behaves like a switched LAN, you must understand which frames Pub Date: October need to flow over 01, the2003 network and which do not. On a typical LAN, the frames traversing the ISBN: 1-58705-096-X network could be data frames or control frames. Some Ethernet services support delivery of all types Pages: of Ethernet 240 protocol data units (PDUs); others may not. To ensure the full functionality of the subscriber network, it is important to have an agreement between the subscriber and the metro carriers on which frames get carried. The EVC service attribute can define whether a particular frame is discarded, delivered unconditionally, or delivered conditionally for each ordered UNI pair. The different possibilities of the Ethernet data frames are as follows:

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Unicast frames— These are frames that have a specified destination MAC address. If the destination MAC address is knownin by the network, the frame getsand delivered to the exact Discover the latest developments metro networking, Ethernet, MPLS services and destination. If the MAC address is unknown, the LAN behavior is to flood the frame within what they can do for your organization the particular VLAN. Learn from the easy-to-read format that enables networking professionals of all levels to Multicast frames— These are frames that are transmitted to a select group of understand the concepts destinations. This would be any frame with the least significant bit (LSB) of the destination address set to experience 1, except for where all bits of the MACCisco destination address are set Gain from the of broadcast, industry innovator and best-selling Press author, Sam to 1. Halabi, author of Internet Routing Architectures Broadcast frames— IEEE 802.3 defines the broadcast address as a destination MAC Metro networks will emerge as the next area of growth for the networking industry and will address, FF-FF-FF-FF-FF-FF. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Layer 2 Control Processing packets are the different L2 control-protocol packets needed been built to handle the stringent reliability and availability needs for voice. Carriers willfor have to specific applications. For example, BPDU packets are needed for STP. The provider might decide go through fundamental shifts to equip the metro for next-generation data services demanded to tunnel or discard these packets over the EVC, depending on the service. The following is by enterprise customers and consumers. This is not only a technology shift, but also a shift a inlist the of currently standardized L2 protocols that can flow over an EVC: operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. IEEE 802.3x MAC control frames— 802.3.x is an XON/XOFF flow-control mechanism that Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic lets an Ethernet interface send a PAUSE frame in case of traffic congestion on the egress of view. It describes the current metro, which is based on TDM technology, and discusses the the Ethernet switch. The 802.3x MAC control frames have destination address 01-80-C2drivers and challenges carriers will face in transforming the metro to address data services. 00-00-01. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Link Aggregation Control Protocol (LACP)— This protocol allows the dynamic bundling to the delivery of metro data services. With a changing mix of transport technologies, the book of multiple Ethernet interfaces between two switches to form an aggregate bigger pipe. The then examines current and emerging trends, and delves into the role of virtual private networks destination MAC address for these control frames is 01-80-C2-00-00-02. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). IEEE 802.1x port authentication— This protocol allows a user (an Ethernet port) to be authenticated into the network via a back-end server, such as a RADIUS server. The destination MAC address is 01-80-C2-00-00-03. Generic Attribute Registration Protocol (GARP)— The destination MAC address is 0180-C2-00-00-2X.

STP— The destination MAC address is 01-80-C2-00-00-00. All-bridge multicast— The destination MAC address is 01-80-C2-00-00-10.

VLAN Tag Support Attribute
•

VLAN tag support provides another set of capabilities that are important for service frame • Index delivery. Enterprise LANs are single-customer environments, meaning that the end users belong Metro Ethernet to a single organization. VLAN tags within an organization are indicative of different logical By Sam Halabi broadcast domains, such as different workgroups. Metro Ethernet creates a different environment in which the Ethernet network supports multiple enterprise networks that share the same infrastructure, Publisher: Cisco Press and in which each enterprise network can still have its own segmentation. Support for different levels of VLANs and the ability to manipulate VLAN tags become very Pub Date: October 01, 2003 important.
ISBN: 1-58705-096-X Pages: 240 Consider the example of an MTU building in which the metro provider installs a switch in the basement that offers multiple Ethernet connections to different small offices in the building. In this case, from a carrier perspective, each customer is identified by the physical Ethernet interface port that the customer connects to. This is shown in Figure 3-6.

Table of Contents

The definitiveFigure guide to 3-6. Enterprise and Carrier Metro Ethernet applications. Ethernet in Multicustomer Environments Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers willitself face is in easy, transforming metro address data services. Although identifying the customer isolatingthe the trafficto between the different customers becomes an interesting issue and requires some attention on the provider's part. Metro Ethernet adoption metro Ethernet services and how that has led in carriers Without special discusses attention,the traffic might of get exchanged between the different customers the to the delivery of metro data services. With a changing mix of transport technologies, the building through the basement switch. You have already seen in the section "L2 Switching book then examines current emerging trends, and delves into the role of virtual private networks Basics" that VLANs can and be used to separate physical segments into many logical segments; (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic In however, this works in a single-customer environment, where the VLAN has a global meaning. engineering, and MPLS and Generalized MPLS (GMPLS). a multicustomer environment, each customer can have its own set of VLANs that overlap with VLANs from another customer. To work in this environment, carriers are adopting a model very similar to how Frame Relay and ATM services have been deployed. In essence, each customer is given service identifiers similar to Frame Relay data-link connection identifiers (DLCIs), which identify EVCs over which the customer's traffic travels. In the case of Ethernet, the VLAN ID given by a carrier becomes that identifier. This is illustrated in Figure 3-7.

Figure 3-7. Logical Separation of Traffic and Services
[View full size image]

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts In this example, the carrier needs to assign to each physical port a set of VLAN IDs that are Gain from the experience of industry innovator and best-selling Cisco Press author, Sam representative of the services sold to each customer. Customer 1, for example, is assigned VLAN Halabi, author of Internet Routing Architectures 10, customer 2 is assigned VLAN 20, and customer 3 is assigned VLAN 30. VLANs 10, 20, and 30 are carrier-assigned VLANs that are independent of the for customer's internalindustry VLAN assignments. Metro networks will emerge as the next area of growth the networking and will To make that distinction, MEF has given the CE-VLANs to the customer-internal VLANs. represent a major shift in the how data services are name offered to businesses and residential customers. The themselves have existing VLAN assignments (CE-VLANs) that overlap with The customers metro has always beencan a challenging environment for delivering data services because it has each and the carrier's VLAN.reliability There are twoavailability types of VLAN tag support: been other built to handle the stringent and needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the VLAN Tag Preservation/Stacking operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. VLAN Tag Translation/Swapping Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the VLAN Preservation/Stacking drivers Tag and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the all adoption of metro Ethernet and how that has led carriers With VLAN Tag Preservation, Ethernet frames receivedservices from the subscriber need to be carried to the delivery of metro data services. With a changing mix of transport technologies, the book untouched within the provider's network across the EVC. This means that the VLAN ID at the then examines current and emerging trends, and delves into the role of virtual private networks ingress of the EVC is equal to the VLAN ID on the egress. This is typical of services such as LAN (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic extension, where the same LAN is extended between two different locations and the enterpriseengineering, and MPLS and Generalized MPLS (GMPLS). internal VLAN assignments need to be preserved. Because the carrier's Ethernet switch supports multiple customers with overlapping CE-VLANs, the carrier's switch needs to be able to stack its own VLAN assignment on top of the customer's VLAN assignment to keep the separation between the traffic of different customers. This concept is called 802.1Q-in-802.1Q or Q-in-Q stacking, as explained earlier in the section "VLAN Tagging." With Q-in-Q, the carrier VLAN ID becomes indicative of the EVC, while the customer VLAN ID (CE-VLAN) is indicative of the

internals of the customer network and is hidden from the carrier's network.

WARNING
The Q-in-Q function is not standardized, and many vendors have their own variations. Table of Contents For the service to work, the Q-in-Q function must work on a "per-port" basis, meaning • Index that each customer can be tagged with a different carrier VLAN tag. Some enterprise Metroswitches Ethernet on the market can perform a double-tagging function; however, these BySam switches Halabi can assign only a single VLAN-ID as a carrier ID for the whole switch. These types of switches work only if a single customer is serviced and the carrier wants to be able toCisco carry the customer VLANs transparently within its network. These switches do Publisher: Press not work when the carrier switch is servicing multiple customers, because it is Pub Date: October 01, 2003 impossible to differentiate between these customers using a single carrier VLAN tag.
•
ISBN: 1-58705-096-X Pages: 240

VLAN Tag Translation/Swapping
VLAN Tag Translation Swapping occurs when the Ethernet VLAN tags are local to the UNI, meaning The definitive guide toor Enterprise and Carrier Metro applications. that the VLAN tag value, if it exists on one side of the EVC, is independent of the VLAN tag values on the other side. In the case where one side of the EVC supports VLAN tagging and the other Discover side doesn't, the carrier removes in the VLAN tag from the Ethernetand frames before they are the latest developments metro networking, Ethernet, MPLS services and delivered the can destination. whatto they do for your organization Another case is two that have merged and want to tie their LANs together, but the Learn from theorganizations easy-to-read format that enables networking professionals of all levels to internal VLAN assignments of each organization do not match. The provider can offer a service understand the concepts where the VLANs are removed from one side of the EVC and are translated to the correct VLANs on the Gain other from side the of experience the EVC. Without of industry this service, innovator the and only best-selling way to join Cisco the two Press organizations author, Samis via IP Halabi, routing, author which of ignores Internet the Routing VLAN assignments Architectures and delivers the traffic based on IP addresses. Metro networks will emerge as the next area of growth for the networking industry and will represent Another example a majorof shift tag in translation how data is services a scenario are offered where different to businesses customers and residential are given Internet customers. The metro has connectivity to always an ISP.been The carrier a challenging gives each environment customer for a separate delivering EVC. data The services carrierbecause assigns it its has beenVLAN-ID own built to handle to the the EVCstringent and strips reliability the VLAN and tagavailability before handing needs off for the voice. traffic Carriers to the will ISP. have This to is go throughin illustrated fundamental Figure 3-8. shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Figure 3-8. VLAN Translation offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 3-8 shows the metro carrier delivering Internet connectivity to three customers. The carrier is receiving untagged frames from the CPE routers located at each customer premises. The carrier inserts a VLAN tag 10 for all of customer 1's traffic, VLAN 20 for customer 2's traffic, and VLAN 30 for customer 3's traffic. The carrier uses the VLAN tags to separate the three customers' traffic within its own network. At the point of presence (POP), the VLAN tags are removed from all EVCs and handed off to an ISP router, which is offering the Internet IP service.
•
Metro Ethernet

Table of Contents

Service Multiplexing Attribute • Index
Service multiplexing is used to support multiple instances of EVCs on the same physical BySam Halabi connection. This allows the same customer to have different services with the same Ethernet wire.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Bundling Attribute Pages: 240

The Bundling service attribute enables two or more VLAN IDs to be mapped to a single EVC at a UNI. With bundling, the provider and subscriber must agree on the VLAN IDs used at the UNI and the mapping between each VLAN ID and a specific EVC. A special case of bundling is where every VLAN ID at the UNI interface maps to a single EVC. This service attribute is called all-toThe definitive guide to Enterprise and Carrier Metro Ethernet applications. one bundling. Discover the latest developments in metro networking, Ethernet, and MPLS services and

Security Attribute whatFilters they can do for your organization

Learn from the easy-to-read format that enables networking professionals of all levels to Security filters are MAC access lists that the carrier uses to block certain addresses from flowing understand the concepts over the EVC. This could be an additional service the carrier can offer at the request of the subscriber who would like a level of protection against certain MAC addresses. MAC addresses Gain from the experience industry innovator and best-selling Cisco Press author, Sam that match a certain access list of could be dropped or allowed. Halabi, author of Internet Routing Architectures Tables 3-1 and 3-2 summarize the Ethernet service attributes and their associated parameters Metro networks will emerge as the next area of growth for the networking industry and will for UNI and EVCs. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This isService not only aAttribute technology shift, but also a shift in the Table 3-1. UNI operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

UNIService Attribute Physical medium Speed Mode
•

Parameter Values or Range of Values A standard Ethernet physical interface. 10 Mbps, 100 Mbps, 1 Gbps, or 10 Gbps. Full-duplex or autospeed negotiation.

MAC layer

Table of Contents

Ethernet and/or IEEE 802.3-2002. Yes or no. If yes, all-to-one bundling must be no. Yes or no. Must be no if all-to-one bundling is yes and yes if all-to-one bundling is no. Yes or no. If yes, service multiplexing and bundling must be no. Must be no if bundling is yes. No or one of the following parameters: CIR, CBS, PIR, MBS. If no, no bandwidth profile per UNI is set; otherwise, the traffic parameters CIR, CBS, PIR, and MBS need to be set.

•Service multiplexing Index
Metro Ethernet BySam Halabi

Bundling

All-to-one Publisher: bundling Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Ingress and egress bandwidth profile Pages: per 240 UNI

Ingress and egress bandwidth No or one of the following parameters: CIR, CBS, PIR, MBS. profile per EVC The definitive guide to Enterprise and Carrier Metro Ethernet applications. Ingress and egress bandwidth No or one of the following parameters: CIR, CBS, PIR, MBS. profile per CoS identifier If one of the networking, parameters is chosen, and specify the CoS Discover the latest developments in metro Ethernet, MPLS services and identifier, Delay value, Jitter value, Loss value. what they can do for your organization If no, no bandwidth profile per professionals CoS identifierof isall set; Learn from the easy-to-read format that enables networking levels to otherwise, the traffic parameters CIR, CBS, PIR, and MBS understand the concepts need to be set. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Ingress and author egress of bandwidth No or one of the following parameters: CIR, CBS, PIR, MBS. Halabi, Internet Routing Architectures profile per destination UNI per EVC networks will emerge as the next area of growth for the networking industry and will Metro represent a major shift in how services are offered to businesses and residential customers. Egress bandwidth profile per data No or one of the following parameters: CIR, CBS, PIR, MBS. The metro has always been a challenging environment for delivering data services because it has source UNI per EVC been built to handle the stringent reliability and availability needs for voice. Carriers will have to go Layer through 2 Control fundamental Protocolshifts to equip Process, the metro discard, for or next-generation pass to EVC the data following services control demanded by processing enterprise customers and consumers. protocol This frames: is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. IEEE 802.3x MAC control Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Link Control Protocol (LACP) view. It describes the current metro, which is Aggregation based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. IEEE 802.1x port authentication Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Generic Attribute Registration Protocol (GARP) to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks STP (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Protocols multicast to all bridges in a bridged LAN UNI service activation time Time value

Table 3-2. EVC Service Attributes
EVCService Attribute EVC Type CE-VLAN ID preservation
•CE-VLAN CoS Table of Contents preservation • Index

Type of Parameter Value P2P or MP2MP Yes or no Yes or no Discard, deliver unconditionally, or deliver conditionally for each ordered UNI pair Discard, deliver unconditionally, or deliver conditionally for each ordered UNI pair Discard, deliver unconditionally, or deliver conditionally for each ordered UNI pair Discard or tunnel the following control frames: IEEE 802.3x MAC control

Unicast frame Metro Ethernet
BySam Halabi

delivery

Multicast frame delivery
Publisher: Cisco Press Pub Date: October 2003 Broadcast frame 01, delivery ISBN: 1-58705-096-X Pages: 240

Layer 2 Control Protocol processing

Link Aggregation Controlapplications. Protocol (LACP) The definitive guide to Enterprise and Carrier Metro Ethernet IEEE 802.1x port authentication Discover the latest developments in metro networking, Ethernet, and MPLS services and Generic Attribute Registration Protocol (GARP) what they can do for your organization STP that enables networking professionals of all levels to Learn from the easy-to-read format understand the concepts Protocols multicast to all bridges in a bridged LAN Gain from the experience of industry innovator and best-selling Cisco Press author, Sam EVC service activation time Time value Halabi, author of Internet Routing Architectures EVC availability Time value Metro networks will emerge as the next area of growth for the networking industry and will EVC mean toshift restore Time value are offered to businesses and residential customers. represent a time major in how data services The metro has always been a challenging environment for delivering data services because it has Class of service CoS identifier, Delay value, Jitter value, Loss value been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded This assigns the Class of Service Identifier to the EVC by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Example of an L2 Metro Ethernet Service
This section gives an example of an L2 metro Ethernet service and how all the parameters defined by the MEF are applied. The example attempts to highlight many of the definitions and concepts discussed in this chapter.
• Table of Contents • Index If you have noticed, the concept of VPNs is inherent in L2 Ethernet switching. The carrier VLAN is Metro Ethernet actually a VPN, and all customer sites within the same carrier VLAN form their own user group and exchange traffic independent of other customers on separate VLANs. BySam Halabi

The issue of security arises in dealing with VLAN isolation between customers; however, because Cisco Press the Publisher: metro network is owned by a central entity (such as the metro carrier), security is enforced. Pub Date: October 01, 2003 First of all, the access switches in the customer basement are owned and administered by the ISBN: 1-58705-096-X carrier, so physical access is prevented. Second, the VLANs that are switched in the network are assigned Pages: by 240 the carrier, so VLAN isolation is guaranteed. Of course, misconfiguration of switches and VLAN IDs could cause traffic to be mixed, but this problem can occur with any technology used, not just Ethernet. Issues of security always arise in public networks whether they are Ethernet, IP, MPLS, or Frame Relay networks. The only definite measure to ensure security is to have the customer-to-customer traffic encrypted at the customer sites and to have the customers administer encryption. The definitive guide tothat Enterprise and Carrier Metro Ethernet applications. Figure 3-9 shows an example of an L2 metro Ethernet VPN. This example attempts to show in a practical way how many developments of the parameters and the concepts Ethernet, that are discussed in this chapter Discover the latest in metro networking, and MPLS services and are used. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to Figure 3-9. All-Ethernet L2 Metro Service Example understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 3-9 shows a metro carrier offering an L2 MP2MP VPN service to customer A and a packet leased-line service (comparable to a traditional T1 leased line) to an ISP. In turn, the ISP is

offering Internet service to customers B and C. It is assumed that customer A connects to the carrier via L2 Ethernet switches and customers B and C connect via IP routers. Notice the difference between access ports and trunk ports on the Ethernet switches. The ports connecting the customer's Ethernet switch to the carrier's Ethernet switch are trunk ports, because these ports are carrying multiple VLANs between the two switches. When the carrier's switch port is configured for Q-in-Q, it encapsulates the customers' CE-VLAN tags VLAN 10 and VLAN 20 inside the carrier VLAN 100. On the other hand, the ports connecting the customer router with the carrier switch are access ports and are carrying untagged traffic from the router. Tables 3-3 and • Table of Contents 3-4 describe the UNI and EVC service attributes for customers A, B, and C as defined by the • Index MEF.
Metro Ethernet BySam Halabi

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 A E-LANUNIService Customer Attribute

Table 3-3. Customer A E-LAN UNI Service Attributes

Parameter Values or Range of Values Standard Ethernet physical interfaces

Physical medium

Speed 100 Mbps site 1, 10 Mbps sites 2 and 3 The definitive guide to Enterprise and Carrier Metro Ethernet applications. Mode Full duplex all sites MAC layer IEEE 802.3-2002 Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organizationNo Service multiplexing Bundling No Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts All-to-one bundling Yes Gain from the experience industry and 1: best-selling Cisco Press author, Sam Ingress and egress bandwidth of profile per innovator All sites CoS Halabi, author of Internet Routing Architectures CoS identifier Metro networks will emerge as the next area of growth the networking industry CIR = for 1 Mbps, CBS = 100 KB, PIRand = 2will Mbps, represent a major shift in how data services are offered businesses and residential customers. MBS = to 100 KB The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability CoS ID = 802.1p needs for 6–7 voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Delay < ms, Loss shift, < 1%but also a shift in the by enterprise customers and consumers. This is not only a10 technology operational and business model that will allow the incumbent carriers to transform the metro to All sites CoS 0: offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic CIR = TDM 1 Mbps, CBS = 100 KB, PIR = 10 Mbps, view. It describes the current metro, which is based on technology, and discusses the MBS = 100 KB drivers and challenges carriers will face in transforming the metro to address data services. CoS ID = 802.1p 0–5, Delay 35 led ms, Loss < Metro Ethernet discusses the adoption of metro Ethernet services and how that< has carriers 2% to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Layer 2 Control Protocol processing Process IEEE 802.3x MAC control Process Link Aggregation Control Protocol (LACP) Process IEEE 802.1x port authentication
• •
Metro Ethernet BySam Halabi

Table of Contents Index

Pass Generic Attribute Registration Protocol (GARP) Pass STP Pass protocols multicast to all bridges in a bridged LAN One hour after equipment is installed

Publisher: Cisco Press Pub Date: October 01, 2003

UNI service activation time ISBN: 1-58705-096-X
Pages: 240

Note in Table 3-3 that customer A is given only one MP2P EVC; hence, there is no service multiplexing. All customer VLANs 10 and 20 are mapped to the MP2MP EVC in the form of carrier VLAN 100. Customer A is given two Class of Service profiles—CoS 1 and CoS 0. Each profile has its set of performance attributes. Profile 1, for example, is applied to high-priority traffic, as indicated by 802.1p priority levels 6 and 7. Profile 0 Ethernet is lower priority, with less-stringent The definitive guide to Enterprise and Carrier Metro applications. performance parameters. For customer A, the metro carrier processes the 802.3x and LACP frames on the UNI connection and passes other L2 control traffic that belongs to the customer. Passing the STP control for example, prevents any potential loops withinservices the customer Discover the latest packets, developments in metro networking, Ethernet, and MPLS and network, in case thedo customer any L2 backdoor direct connection between its different sites. what they can for yourhas organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industryA innovator best-selling Press author, Sam Table 3-4. Customer E-LAN and EVC ServiceCisco Attributes Halabi, author of Internet Routing Architectures Customer A E-LAN EVCService Metro networks will emerge as the next area of growth for the networking industry and will Attribute Type of Parameter Value represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has EVC type MP2MP been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip Yes the metro for next-generation data services demanded CE-VLAN ID preservation by enterprise customers and consumers. This is not only a technology shift, but also a shift in the CE-VLAN CoS preservation Yes operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Unicast frame delivery Deliver unconditionally for each UNI pair Metro Ethernet from Cisco Press looks at the deployment of metro data UNI services Multicast frame delivery Deliver unconditionally for each pair from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Broadcast delivery unconditionally for each UNI pair drivers and frame challenges carriers will faceDeliver in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Layer 2 Control Protocol processing

Tunnel the following control frames: IEEE 802.3x MAC control Link Aggregation Control Protocol (LACP)

• •
Metro Ethernet BySam Halabi

Table of Contents Index

IEEE 802.1x port authentication Generic Attribute Registration Protocol (GARP) STP Protocols multicast to all bridges in a bridged LAN Twenty minutes after UNI is operational Three hours One hour All sites CoS 1:

Publisher: Cisco Press

EVC service activation time Pub Date: October 01, 2003 EVC availability
Pages: 240 ISBN: 1-58705-096-X

EVC mean time to restore Class of service

CoS ID Ethernet = 802.1papplications. 6–7 The definitive guide to Enterprise and Carrier Metro Delay < 10 ms, Loss < 1%, Jitter (value) Discover the latest developments in metro networking, Ethernet, and MPLS services and All sites CoS 0: what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to CoS ID = 802.1p 0–5, Delay < 35 ms, Loss < 2%, understand the concepts Jitter (value) Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Architectures The EVC service parameters forRouting customer A indicate that the EVC is an MP2MP connection and the carrier transparently moves the customer VLANs between sites. The carrier does this using Metro networks will emerge as theVLAN next area growth for the also networking industry Q-in-Q tag stacking with a carrier ID ofof 100. The carrier makes sure thatand the will 802.1p represent a major shift in how data services are offered to businesses and residential customers. priority fields that the customer sends are still carried within the network. Note that the carrier The metro has always been a challenging environment for delivering data because it has allocates priority within its network whichever way it wants as long as the services carrier delivers the been built to handle the stringent reliability and availability needs for voice. Carriers will have to SLA agreed upon with the customer as described in the CoS profiles. For customer A, the carrier go through fundamental shifts to equip the metro for next-generation data services demanded passes all unicast, multicast, and broadcast traffic and also tunnels all L2 protocols between the by enterprise customers and consumers. This is not only a technology shift, but also a shift in the different sites. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced services. Tables 3-5 and data 3-6 describe customers B and C and ISP POP service profile for the Internet connectivity service. These are the service attributes and associated parameters for customers B Metro from Cisco Press looks at the deployment of metro for data services from a holistic and C Ethernet as well as the service attributes and associated parameters the ISP POP offering view. It describes the current metro, which is based on TDM technology, and discusses the Internet connectivity to these customers. drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the roleService of virtual private networks Table 3-5. Customers B and C and ISP POP UNI Attributes (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Customers B and C and ISPPOPInternet AccessUNIService Attribute Physical medium Speed
•Mode •
Metro Ethernet

Parameter Values or Range of Values Standard Ethernet physical interfaces 10 Mbps for customers B and C, 100 Mbps for the ISP POP

Table of Contents Index

Full duplex all sites IEEE 802.3-2002 Yes, only at ISP POP UNI No No Customers B and C CIR = 1 Mbps, CBS = 100 KB, PIR = 2 Mbps, MBS = 100 KB ISP POP

MAC layer

Service multiplexing By Sam Halabi Bundling All-to-one bundling Pub Date: October 01, 2003
ISBN: 1-58705-096-X Ingress and egress bandwidth profile per EVC Pages: 240 Publisher: Cisco Press

The definitive guide to Enterprise and Carrier Metro Ethernet applications. CIR = 10 Mbps, CBS = 1 MB, PIR = 100 Mbps, MBS = 1 MB Discover the latest developments and control MPLS services Layer 2 Control Protocol processing in metro networking, Discard Ethernet, the following frames:and what they can do for your organization Learn from the easy-to-read format that enables networking IEEE 802.3x professionals MAC control of all levels to understand the concepts Link Aggregation Control Protocol Gain from the experience of industry innovator and best-selling (LACP) Cisco Press author, Sam Halabi, author of Internet Routing Architectures IEEE 802.1x port authentication Metro networks will emerge as the next area of growth for the networking industry and will Attribute Registration represent a major shift in how data services are offered toGeneric businesses and residential customers. (GARP) The metro has always been a challenging environment for Protocol delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to STP go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Protocols multicast to all the bridges in to a operational and business model that will allow the incumbent carriers to transform metro bridged LAN offer enhanced data services. UNI service activation time One hour after equipment is installed Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the For customers B and C carriers and ISP will POPface UNIin service parameters, because two different P2P EVCs drivers and challenges transforming the metro to address data services. (carrier VLANs 200 and 300) are configured between the customers and the ISP POP, service multiplexing occurs at thethe ISP UNI connection where two services EVCs are multiplexed the Metro Ethernet discusses adoption of metro Ethernet and how that on has ledsame carriers physical connection. For data this Internet the customer premises to the delivery of metro services.access With ascenario, changingrouters mix of are transport technologies, the book equipment, so it is unlikely that the customer will delves send any L2 control-protocol packetsnetworks to the then examines current and emerging trends, and into the role of virtual private carrier.virtual In anyprivate case, all L2 control-protocol packets are discarded if any occur. (VPLS), traffic (VPN), local area networks (VLAN), virtual private LAN services engineering, and MPLS and Generalized MPLS (GMPLS).

Table 3-6. Customers B and C and ISP POP EVC Service Attributes

Customers B and C and ISPPOPInternet AccessEVCService Attribute EVC type CE-VLAN ID preservation CE-VLAN CoS preservation
• •

Type of Parameter Value P2P No; mapped VLAN ID for provider use No Deliver unconditionally for each UNI pair Deliver unconditionally for each UNI pair Deliver unconditionally for each UNI pair Discard the following control frames: IEEE 802.3x MAC control Link Aggregation Control Protocol (LACP) IEEE 802.1x port authentication

Unicast frame delivery
Index

Table of Contents

Metro Ethernet Multicast frame BySam Halabi

delivery

Broadcast frame delivery Layer 2 Control Protocol processing Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Generic Attribute Registration Protocol (GARP) Discover the latest developments in metro networking, Ethernet, and MPLS services and STP what they can do for your organization Protocols multicast to all bridges in Learn from the easy-to-read format that enables networking professionals of all levels to a bridged LAN understand the concepts EVC service activation time Twenty minutes after UNI is operational Gain from the experience of industry innovator and best-selling Cisco Press author, Sam EVC Halabi, availability author of Internet Routing Architectures Three hours EVC mean timewill to restore hour Metro networks emerge as the next area of growth One for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Class of service One CoS service is supported: The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs voice. Carriers will (value) have to Delay < 30 for ms, Loss < 1%, Jitter go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. Thisis isnot not preserving only a technology shift, but alsoor a shift in the The EVC parameters indicate that the carrier any customer VLANs CoS info. operational and business model that will allow the incumbent carriers to transform the metro to Also, because this is an Internet access service, normally the provider receives untagged frames offer enhanced data services. from the CPE router. The provider can map those frames to carrier VLANs 200 and 300 if it needs to separate the traffic in its network. The VLAN IDs are normally stripped off before given Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic to the ISP router. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Challenges w ith All-Ethernet Metro Networks
All-Ethernet metro networks pose many scalability and reliability challenges. The following are some of the issues that arise with an all-Ethernet control plane:
• •
Metro Ethernet BySam Halabi

Table of Contents

Restrictions Index on the number of customers Service monitoring Scaling the L2 backbone
Publisher: Cisco Press

Service provisioning Pub Date: October 01, 2003 Interworking with legacy deployments
Pages: 240 ISBN: 1-58705-096-X

The following sections describe each of these challenges.

Restrictions on the Number of Customers The definitive guide to Enterprise and Carrier Metro Ethernet applications.
The Ethernet control plane restricts the carrier to 4096 customers, because the 802.1Q defines 12 bits that can belatest used developments as a VLAN ID, in which restricts the number of VLANs to 212 = 4096. Discover the metro networking, Ethernet, and MPLS services and Remember that can although allows the customer VLANs (CE-VLANs) to be hidden from the what they do forQ-in-Q your organization carrier network, the carrier is still restricted to 4096 VLAN IDs that are global within its network. Learn from the that easy-to-read format that enables networking professionals all levels to For many operators are experimenting with the metro Ethernet service, theof 4096 number understand the for concepts seems good enough an experimental network but presents a long-term roadblock if the service is to grow substantially. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

Service Monitoring Metro networks will emerge as the next area of growth for the networking industry and will
represent a major shift in how data services are offered to businesses and residential customers. The metro Ethernet does hasnot always have been an embedded a challenging mechanism environment that lends for delivering to service data monitoring. services because With Frame it has been built Relay LMI,to for handle example, the stringent service monitoring reliability and and service availability integrity needs are for facilitated voice. Carriers via messages will have that to go through report the status fundamental of the PVC. shifts Ethernet to equip service the metro monitoring for next-generation requires additional data services control-plane demanded by enterprise intelligence. New customers Link Management and consumers. Interface This (LMI) is not protocols only a technology need to be shift, defined but also and a instituted shift in the operational between the and service business provider model network that will and allow the CPE the incumbent to allow the carriers customer to transform to discover the the metro different to offer enhanced EVCs that exist data on the services. UNI connection. The LMI could learn the CE-VLAN to EVC map and could learn the different service parameters such as bandwidth profiles. Other protocols need to be Metro Ethernet from Cisco Press of looks the of metro dataYou services defined to discover the integrity the at EVC indeployment case of possible failures. have from seen a inholistic the view. It describes the performance current metro, which is based TDM technology, and of discusses previous section how parameters could on indicate the availability an EVC. the Protocols drivers and challengesfrom carriers transforming metrosuch to address data services. to extract information the will UNIface and in EVC are neededthe to make information usable. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Scaling the current L2 Backbone then examines and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic A metro carrier that is building an all-Ethernet network is at the mercy of STP. STP blocks engineering, and MPLS and Generalized MPLS (GMPLS). Ethernet ports to prevent network loops. Traffic engineering (discussed in Chapter 5, "MPLS Traffic Engineering") is normally a major requirement for carriers to have control over network bandwidth and traffic trajectory. It would seem very odd for any carrier to have the traffic flow in its network be dependant on loop prevention rather than true bandwidth-optimization metrics.

Service Provisioning
Carrying a VLAN through the network is not a simple task. Any time a new carrier VLAN is created (a new VPN), care must be taken to configure that VLAN across all switches that need to participate in that VPN. The lack of any signaling protocols that allow VPN information to be exchanged makes the task manual and tedious. Early adopters of metro Ethernet have endured the pains of carrying VLANs across many switches. Even with the adoption of new protocols such • Table of Contents as 802.1s ("Amendment to 802.1Q (TM) Virtual Bridged Local Area Networks: Multiple Spanning • Index Trees"), the task of scaling the network is almost impossible.
Metro Ethernet BySam Halabi

Interworking with Legacy Deployments
Publisher: Cisco Press

Another challenge facing Ethernet deployments is interworking with legacy deployments such as ISBN: 1-58705-096-X existing Frame Relay and ATM networks. Frame Relay has been widely deployed by many Pages: 240 enterprises as a WAN service. Remote offices are connected to headquarters via P2P Frame Relay circuits forming a hub-and-spoke topology. Enterprises that want to adopt Ethernet as an access technology expect the carrier to provide a means to connect the new sites enabled with Ethernet access with existing headquarters sites already enabled with Frame Relay. This means that a function must exist in the network that enables Frame Relay and Ethernet services to work together. The definitive guide to Enterprise and Carrier Metro Ethernet applications. The IETF has standardized in RFC 2427, Multiprotocol Interconnect over Frame Relay, how to carry Discover different the protocols latest developments over Frame Relay, in metro including networking, Ethernet. Ethernet, In some and other MPLS cases, services the Ethernet and and Frame what they Relay can access do for networks your organization are connected by an ATM core network. In this case, two service-interworking functions need to happen, one between Ethernet and ATM and another Learn from the easy-to-read format that enables networking professionals all 2684, levels and to between ATM and Frame Relay. Ethernet-to-ATM interworking is achieved using of RFC understand the concepts ATM-to-Frame Relay interworking is achieved via the Frame Relay Forum specification FRF 8.1. Figure 3-10 illustrates the service-interworking functions. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

Pub Date: October 01, 2003

Figure 3-10. Service Interworking

Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 3-10 shows a scenario in which an enterprise headquarters is connected to its remote sites via Frame Relay connections carried over an ATM network. The different serviceinterworking functions are displayed to allow such networks to operate. For service interworking, two encapsulation methods are defined: one is bridged, and the other is routed. Both sides of the connection are either bridged or routed. Some challenges might exist if one end of the connection is connected to a LAN switch, and hence bridged, while the other end is connected to a router. Other issues will arise because of the different Address Resolution Protocol (ARP) formats between the different technologies, such as Ethernet, Frame Relay, and ATM. Some • Table of Contents vendors are attempting to solve these problems with special software enhancements; however, • Index such practices are still experimental and evolving.
Metro Ethernet By Halabi It Sam is all these challenges that motivated the emergence of hybrid architectures consisting of multiple L2 domains that are connected via L3 IP/MPLS cores. The network can scale because L2 Ethernet would constrained to more-controlled access deployments that limit the VLAN and Publisher: Cisco be Press STPPub inefficiencies. The network can then be scaled by building a reliable IP/MPLS core. This is Date: October 01, 2003 discussed in Chapter 4, "Hybrid L2 and L3 IP/MPLS Networks." ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
This chapter has discussed many aspects of metro Ethernet services. The MEF is active in defining the characteristics of these services, including the service definitions and framework and the many service attributes that make up the services. Defining the right traffic and performance • Contents parameters, Table classof of service, service frame delivery, and other aspects ensures that buyers and • Index users of the service understand what they are paying for and also helps service providers Metro Ethernet their capabilities. communicate
BySam Halabi

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 4. Hybrid L2 and L3 IP/MPLS Networks
• of Contents This chapter Table covers the following topics: •
Metro Ethernet BySam Halabi

Index

Understanding VPN Components Delivering L3VPNs over IP

Publisher: Cisco Press

L2 Ethernet Pub Date: October Services 01, 2003
ISBN: 1-58705-096-X

over an IP/MPLS Network

InChapter 3, "Metro Ethernet Services," you reviewed the issues that can be created by an L2Pages: 240 only Ethernet model. This chapter first focuses on describing a pure L3VPN implementation and its applicability to metro Ethernet. This gives you enough information to compare L3VPNs and L2VPNs relative to metro Ethernet applications. The chapter then delves into the topics of deploying L2 Ethernet services over a hybrid L2 Ethernet and L3 IP/MPLS network. Some of the basic scalability issues to be considered include restrictions on the number of customers because The definitive guide to Enterprise and Metro Ethernet applications. of the VLAN-ID limitations, scaling theCarrier L2 backbone with spanning tree, service provisioning and monitoring, and carrying VLAN information within the network. The following section describes some basic VPN definitions and terminology. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Understanding VPN Components
There are normally two types of VPNs: customer premises equipment-(CPE) based VPNs and network-based VPNs. With CPE-based VPNs, secure connections are created between the different customer premises equipment to form a closed user group/VPN. This normally creates • Table of Contents scalability issues, because many CPE devices have to be interconnected in a full mesh or a • Index partial mesh to allow point-to-multipoint connectivity. On the other hand, network-based VPNs Metro Ethernet create some level of hierarchy where connections from many CEs are aggregated into an edge switch or router offering the VPN service. By Sam Halabi The definitions of the different elements of the network follow:
Publisher: Cisco Press Pub Date: October 01, 2003

Customer ISBN: 1-58705-096-X edge (CE)— The customer edge device resides at the edge of the enterprise. This device is usually a router or a host in L3VPNs; however, as you will see with L2VPNs, Pages: 240 the CE could also be an L2 switch. The CE connects to the provider network via different data-link protocols such as PPP, ATM, Frame Relay, Ethernet, GRE, and so on. Provider edge (PE)— The provider edge device is a provider-owned device that offers the first level of aggregation for the different CEs. The PE logically separates the different VPNs The definitive guidein. to The Enterprise and Carrier Metro Ethernet it participates PE does not have to participate in applications. all VPNs but would only participate in the VPNs of the enterprises that are directly attached to it. Discover the latest developments in metro networking, Ethernet, and MPLS services and Provider (P)— The provider device is normally a core IP/MPLS router that offers a second what they can do for your organization level of aggregation for the PEs. This device does not participate in any VPN functionality and is from normally agnostic to the presence of any VPNs. Learn the easy-to-read format that enables networking professionals of all levels to understand the concepts The remainder of the chapter mainly focuses on different types of VPNs and how they differ between an L2 or L3 service. The types of VPNs include Gain from the experience of different industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures GRE- and MPLS-based L3VPNs Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in IP/MPLS how dataL2VPNs services are offeredEthernet to businesses and residential Hybrid Ethernet and via L2TPv3, over MPLS (EoMPLS),customers. and The metro has always been a challenging environment for delivering data services because it has Virtual Private LAN Service (VPLS) been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Delivering L3VPNs over IP
L3VPNs allow the provider to extend its customer's private IP network over the provider's backbone. When delivering an L3 service, the service provider is normally involved in the assignment and management of a pool of IP addresses allocated to its customer. This is typical • Table of also Contents of carriers that are ISPs offering Internet services or carriers offering IP multicast services • Index and so on. L3VPNs can be delivered via GRE tunnels or MPLS L3VPNs.
Metro Ethernet BySam Halabi

GRE-Based VPNs
Publisher: Cisco Press Pub Date: October 01, IP 2003 L3VPN services over have traditionally been done using generic routing encapsulation (GRE) ISBN: 1-58705-096-X tunnels, which allow the encapsulation of IP packets inside IP packets. GRE-based VPNs are CEbasedPages: VPNs. A network hierarchy can be maintained in which an enterprise that has, for 240 example, a private IP addressing scheme can create a private VPN on top of a service provider's network. IP forwarding is used to exchange traffic between the endpoints of GRE tunnels, allowing full or partial connectivity between the different sites of the same enterprise. From a scalability perspective, this scheme could scale to a certain point and then become unmanageable, because the VPN becomes the collection of many point-to-point tunnels. As The definitive guide to Enterprise and Carrier Metro Ethernet applications. many sites are added to the VPN and many tunnels have to be created to all or a partial set of the other sites, the operational management of such a scheme becomes cost-prohibitive, especially because there developments are no rules or guidelines or an industry push and to allow such tunneling Discover the latest in metro networking, Ethernet, MPLS services and schemes tothey scale. what can do for your organization

Figure 4-1 shows an easy-to-read example of a format servicethat provider delivering a GRE-based VPN service using Learn from the enables networking professionals of all levels to managed CEs located at different enterprise sites. The provider is managing the CEs at each site understand the concepts of each enterprise and is managing the tunnel connectivity between the different sites. As the number of from enterprises grows and number of sites per best-selling enterprise grows as well, this model Gain the experience of the industry innovator and Cisco Press author, Sam will definitely have scalability issues. Notice that different enterprises could use overlapping Halabi, author of Internet Routing Architectures private IP addresses, because all IP and routing information between the enterprise sites is Metro networks will emerge as the area of growth for the network networking industry and will carried within tunnels and hence is next hidden from the provider's and other enterprises. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Figure 4-1. GRE Tunnels been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and For large-scale of IP VPNs, the industry has gradually moved toward adopting what they deployments can do for your organization MPLS L3VPNs, as defined in RFC 2547. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

MPLS L3VPNs

Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures MPLS L3VPNs are network-based VPNs. This scheme defines a scalable way for the service provider to offerwill VPN services enterprises. Enterprises theindustry service provider Metro networks emerge asfor the next area of growth forcan the leverage networking and will backbone to globally expand their intranets and extranets. An intranet normally means that all represent a major shift in how data services are offered to businesses and residential customers. sites in the VPN connect to the same customer, and extranet means that the various sites init the The metro has always been a challenging environment for delivering data services because has VPN are owned by different enterprises, such as the suppliers of an enterprise. An example of been built to handle the stringent reliability and availability needs for voice. Carriers will have an to extranet would be a car manufacturer that network that connects and all its parts go through fundamental shifts to equip the builds metro a for next-generation datait services demanded suppliers in a customers private network. by enterprise and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Although MPLS data L3VPNs provide a sound and scalable solution for delivering VPNs over IP, they offer enhanced services. have some characteristics that make them overkill for metro Ethernet services. L3VPNs, for example, are more adequate for looks delivering IP services than services. Thisfrom is one the Metro Ethernet from Cisco Press at the deployment of L2VPN metro data services a of holistic reasons that the industry is looking at L2VPNs for metro Ethernet services. To understand the view. It describes the current metro, which is based on TDM technology, and discusses the differences L2VPNs and L3VPNs, helps to identify the different elements of MPLS drivers and between challenges carriers will face init transforming the metro to address data services. L3VPNs (RFC 2547) and the challenges that come with them. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers MPLS the CE, PE,services. and P terminology described in the technologies, "Understanding VPN to the L3VPNs deliveryuse of metro data With a changing mixearlier of transport the book Components" section. the case where the CE isdelves a router, the CE and become routing peers then examines currentIn and emerging trends, and into the role of PE virtual private networks if a routing protocol islocal usedarea between the two to exchange IP prefixes. In other (VPLS), scenarios, static (VPN), virtual private networks (VLAN), virtual private LAN services traffic routing is used between the Generalized PE and CE to alleviate the exchange of routing information. With engineering, and MPLS and MPLS (GMPLS). L3VPNs, enterprise edge routers have to talk only to their direct neighbor, which is the router owned by the provider. From a scalability perspective, the L3VPN model scales very well, because each site does not need to know of the existence of other sites. On the other hand, this model is not so good for enterprises that would like to maintain their own internal routing practices and control the routing mechanism used between the different sites. Also, this model

forces the service provider to participate in and manage the IP addressing schemes for its customers, as is typically done when IP services are sold. This model is not adequate for selling L2 services only (L2VPN) where the customer's IP network becomes an overlay on top of the service provider's network. Another disadvantage of L3VPNs when used for metro Ethernet services is that L3VPNs apply only to the transport of IPv4 packets. For metro deployments, enterprise traffic consists of IPv4 as well as other types of traffic such as IPX and SNA. An L2VPN allows any type of traffic to be • Table of Contents encapsulated and transported across the metro network.
• Index
Metro Take Ethernet a close look

at the example in Figure 4-2. The provider is delivering VPN services to two different By Sam Halabi enterprises, A and B, and each enterprise has two different sites. Sites A1 and A2 are part of enterprise A and belong to VPN-A. Sites B1 and B2 are part of enterprise B and belong to VPN-B. Note that enterprises A and B could have overlapping IP addresses. The following are the Publisher: Cisco Press reasons why the MPLS L3VPN model scales: Pub Date: October 01, 2003
ISBN: 1-58705-096-X Pages:PE 240 Each knows only of the VPNs it attaches to. PE1 knows only of VPN-A, and PE3 knows only of VPN-B.

The P routers do not have any VPN information. The CE routers peer with their directly attached PEs. A1 peers with PE1, B1 peers with PE3, The definitive guide to Enterprise and Carrier Metro Ethernet applications. and so on. Discover the latest developments inMPLS metro networking, Ethernet, and MPLS services and Figure 4-2. L3VPN Principles what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. The following sections describe Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the How MPLS L3VPN PEs maintain separate forwarding tables between different VPNs drivers and challenges carriers will face in transforming the metro to address data services. The concept of VPN-IPv4 addresses Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a backbone changing mix ofthe transport technologies, the book How packets are transported across the using MPLS L3VPN mechanism then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Maintaining Site Virtual Router Forwarding Tables

The fundamental operation of the MPLS L3VPN model follows: Each PE router maintains a separate virtual router forwarding (VRF) table for each site the

PE is attached to. The forwarding table contains the routes to all other sites that participate in a set of VPNs. The PEs populate the forwarding tables from information learned from the directly attached sites or learned across the backbone from other PEs that have a VPN in common. Information from directly attached CEs is learned via routing protocols such as OSPF, ISIS, RIP, and BGP or via static configuration. Distribution of VPN information across the backbone is done via multiprotocol BGP (MP-BGP). MP-BGP introduces extensions to the • Table of Contents BGP-4 protocol to allow IPv4 prefixes that are learned from different VPNs to be exchanged • Index across the backbone. IP prefixes can overlap between different VPNs via the use of VPNMetro Ethernet IPv4 address, as explained later, in the section "Using VPN-IPv4 Addresses in MPLS BySamL3VPNs." Halabi The CEs learn from Publisher: Cisco Press the PEs about the routes they can reach via routing protocols or static

configuration. Pub Date: October 01, 2003

1-58705-096-X Traffic ISBN: is forwarded across the backbone using MPLS. MPLS is used because the backbone P Pages: 240 routers have no VPN routes; hence, traditional IP routing cannot be used. Figure 4-3 illustrates the packet forwarding process.

Figure 4-3. The Packet Forwarding Process
The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to AsFigure 4-3 shows, when a packet is received from a site, the PE looks up the IP destination in offer enhanced data services. the site's forwarding table and, if found, forwards the packet via MPLS. Otherwise, the PE checks the destination in other forwarding tables and discards the packet if no match has been made. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Figure 4-4 shows how the PEs maintain a different forwarding table per site. PE1 contains a drivers and challenges carriers will face in transforming the metro to address data services. forwarding table for enterprise A site 1 (A1). That forwarding table is populated from routes learned from A1 and from BGP routes across the backbone. PE2 contains a forwarding table for Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers both enterprise A site 2 (A2) and enterprise B site 2 (B2). to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks Figure 4-4. PE Logical Separation (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

MPLS L3VPNs use target VPNs, VPN of origin, and site of origin to be able to identify and The definitive guide toroutes Enterprise and Carrier MetroVPNs Ethernet separate the different belonging to different and applications. to clearly identify the origin of a particular route. The following sections describe these features. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

Target VPN

Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts For identifying different VPNs, every per-site forwarding table is associated with one or more target VPN attributes. When a PE router creates a VPN-IPv4 route, the route is associated with Gain from the VPN experience of industry innovator best-selling Cisco Press author, Sam one or more target attributes, which are carried and in BGP as attributes of the route. A route Halabi, author of Internet Routing Architectures attribute is a parameter that gives the route special characteristics and is a field that is distributed inside a BGP advertisement. The target VPN attribute identifies a set of sites. Metro networks will emerge as the next area of growth for the networking industry and will Associating a particular target VPN attribute with a route allows the route to be placed in the represent a major shift in how data services are offered to businesses and residential customers. per-site forwarding tables used for routing traffic that is received from the corresponding site. In The metro has always been a challenging environment for delivering data services because it has Figure 4-4, when PE1 receives BGP routes from PE2, PE1 installs in the A1 forwarding table only been built to handle the stringent reliability and availability needs for voice. Carriers will have to routes that have a target VPN attribute VPN-A. This ensures that PE1 does not contain any go through fundamental shifts to equip the metro for next-generation data services demanded routes to VPN-B, because PE1 does not have any attached sites that belong to VPN-B. On the by enterprise customers and consumers. This is not only a technology shift, but also a shift in the other hand, PE2 installs in the respective forwarding tables routes that belong to VPN-A and operational and business model that will allow the incumbent carriers to transform the metro to VPN-B, because PE2 is attached to sites that belong to both VPNs. offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services.

NOTE

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers In the context of MPLS L3VPN, IPv4 addresses are referred to as VPN-IPv4 addresses. to the delivery of metro data services. With a changing mix of transport technologies, the book The section "Using VPN-IPv4 Addresses in MPLS L3VPNs" discusses scenarios for VPNthen examines current and emerging trends, and delves into the role of virtual private networks IPv4 addresses in more detail. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

VPN of Origin
Additionally, a VPN-IPv4 route may be optionally associated with a VPN of origin attribute. This

attribute uniquely identifies a set of sites and identifies the corresponding route as having come from one of the sites in that set. Typical uses of this attribute might be to identify the enterprise that owns the site where the route leads, or to identify the site's intranet. However, other uses are also possible, such as to identify which routes to accept and which to drop based on the VPN of origin. By using both the target VPN and the VPN of origin attributes, different kinds of VPNs can be constructed.
•
Metro Ethernet

Table of Contents

Site of Origin • Index
Another attribute, called the site of origin attribute, uniquely identifies the site from which the PE BySam Halabi router learned the route (this attribute could be encoded as an extended BGP community attribute). All routes learned from a particular site must be assigned the same site of origin Publisher: Cisco Press attribute.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 Using VPN-IPv4 Addresses in MPLS L3VPNs

The purpose of VPN-IPv4 addresses is to allow routers to create different routes to a common IPv4 address. This is useful in different scenarios that relate to L3VPNs. The definitive guide to Enterprise and Carrier Ethernet applications. One such scenario occurs when multiple VPNs Metro have overlapping IPv4 addresses. In this case, routers need to treat each address differently when populating the per-site forwarding table. If the same address belongs in two different VPNs, the router needs to place the same address into DiscoverVRF the tables. latest developments inVPN-IPv4 metro networking, Ethernet, and MPLS and two different Another use of is to create separate routes to services reach the same what they can do for your organization IPv4 destination address. In the case of an enterprise that has an intranet and an extranet, the same server can have its IP address advertised in two different routes, one used by the intranet Learn from the easy-to-read format that enables networking professionals of all levels to and another by the extranet. The extranet route could be forced to go through a firewall before understand the concepts reaching the server. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam The VPN-IPv4 address, as shown in Figure 4-5, is a 12-byte quantity, beginning with an 8-byte Halabi, author of Internet Routing Architectures Route Distinguisher (RD) and ending with a 4-byte IPv4 address. The RD consists of a Type field that indicates the length of the Administrator and Assigned Number fields. industry The Administrator Metro networks will emerge as the next area of growth for the networking and will field identifies an Assigned Number authority field, such as an autonomous system number given represent a major shift in how data services are offered to businesses and residential customers. to a certain service provider. The service provider can then allocate the assigned number to be The metro has always been a challenging environment for delivering data services because it has used for a particular purpose. Note that the RD by itself does not contain enough information been built to handle the stringent reliability and availability needs for voice. Carriers will haveto to indicate thefundamental origin of the shifts route to or equip to which the needs to be data distributed. In other go through theVPNs metro forroute next-generation services demanded words, the RDcustomers is not indicative of a particular purpose of the shift, RD isbut only to allow the by enterprise and consumers. This VPN. is notThe only a technology also a shift in the router to create different routes to the same IPv4 address. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.

Figure 4-5. VPN-IPv4 Address
Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

As referenced in Figure 4-5, ISP A wants to distinguish between two IPv4 addresses 10.10.10.0; therefore, it assigns these two addresses two different RDs. The RD administrator number is ISP

A's autonomous system (AS) number (1111). The assigned numbers 1 and 2 are just arbitrary numbers that help the routers distinguish between the two IP addresses that could be in the same VPN or different VPNs. Again, it is important to understand that the VPN-IPv4 does not modify the IP address itself but rather is an attribute sent within BGP (RFC 2283) that indicates that the IP address belongs to a certain family.

Forwarding Traffic Across the Backbone • Table of Contents
• Index
Metro Ethernet Only the edge PE routers have information about the VPN IP prefixes. The backbone P routers do not carry any VPN IP prefixes. With traditional IP forwarding, this model does not work, because BySam Halabi the P routers drop any traffic destined for the VPN IP addresses. MPLS is used to allow packet forwarding based on labels rather than IP addresses. The PE routers tag the traffic with the right Publisher: Cisco Press label based on the destination IP address it needs to go to, and the MPLS P routers switch the Pub Date: October 01, 2003 traffic based on the MPLS labels. If this model is not adopted, the P routers would have to carry ISBN: for 1-58705-096-X IP prefixes all VPNs, which would not scale. Pages: 240

MPLS L3VPN does not mandate the use of traffic engineering (a topic that is explained in more detail in Chapter 5, "MPLS Traffic Engineering"). When traffic moves from one site to another across the carrier's backbone, it follows the MPLS label switched path (LSP) assigned for that traffic. The LSP itself could have been formed via dynamic routing calculated by the routing protocols. On the other hand, the and LSP Carrier could be traffic-engineered to allow certain types of traffic The definitive guide to Enterprise Metro Ethernet applications. to follow a well-defined trajectory. Also, many mechanisms can be used for traffic rerouting in case of failure. The mechanism used depends on whether the carrier requires normal IP routing or MPLS fast reroute mechanisms (as explained in Chapter 6, "RSVP for Traffic Engineering and Discover the latest developments in metro networking, Ethernet, and MPLS services and Fast Reroute"). what they can do for your organization The traffic theeasy-to-read MPLS backbone carries label stack. The label on top of the is called Learnacross from the format thataenables networking professionals of stack all levels to the packet-switched network (PSN) tunnel label and is indicative of the path that a packet needs understand the concepts to take from the ingress PE to the egress PE. The label beneath is indicative of the particular VPN that the Gain packet from the belongs experience to. In the of industry case where innovator IP forwarding and best-selling (rather than Cisco MPLS) Press is author, used in Sam the provider Halabi, routers, author the of PSN Internet tunnel Routing can be Architectures replaced by a GRE tunnel, and the packet would carry the VPN label inside the GRE tunnel. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Applicability of MPLS L3VPNs for Metro Ethernet been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded The MPLS L3VPN model presents many challenges if only usedato deliver metro Ethernet by enterprise customers and consumers. This is not technology shift, but alsoservices. a shift inThis the model is more applicable for delivering IP services, where an enterprise is outsourcing operational and business model that will allow the incumbent carriers to transform the the metro to operation of its data WAN/metro IP network to a service provider. From an administration point of offer enhanced services. view, the MPLS L3VPN model dictates that the carrier is involved with the customer's IP addressing scheme. the routers wouldof have to peer the provider's Metro Ethernet from Remember Cisco Pressthat looks atCE the deployment metro data with services from a holistic routers. If static routing is not used, routing exchange between the PE and CE might involve view. It describes the current metro, which is based on TDM technology, and discusses the configuring protocols like RIP and and will the involve many guidelines to allow drivers and routing challenges carriers will face in OSPF transforming metro to address data services. protocols such as OSPF to understand the separation between the different VPN routes and to distribute the correct routes BGP and OSPF. Metro Ethernet discusses thebetween adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book From an equipment vendor perspective, while thedelves MPLS L3VPN model scales in private theory, networks it then examines current and emerging trends, and into the role of virtual introduces major overhead on the edge routers. If virtual you assume that anservices edge router needs to (VPN), virtual private local area networks (VLAN), private LAN (VPLS), traffic support 1000and VPNs, and each VPN has 1000 IP(GMPLS). prefixes, the edge routers would have to engineering, MPLS and Generalized MPLS maintain at least 1,000,000 IP prefixes in 1000 separate forwarding tables. Most routers on the market are still struggling to reach 256,000 to 500,000 IP entries, depending on the vendor's implementation. So what would happen if the IP prefixes per VPN reaches 5000 entries rather than 1000? A clever answer would be to support 200 VPNs per PE router to stay within the 1,000,000 prefix limit, until vendors find a way to increase that number.

There are other ways of deploying L3VPNs, such as using virtual routers where different instances of routing protocols run on each router. Each routing instance carries the IP prefixes of a different VPN, and traffic is forwarded across the network using traditional IP forwarding; hence, the final outcome is very similar to running MPLS L3VPNs. The MPLS L3VPN and virtual routers have their advantages in delivering IP services, which include IP QoS mechanisms, IP address pool management, and so on. These advantages are very important but are outside the scope of this book and will not be discussed. However, L3VPN is still overkill for deploying metro Ethernet services, which focuses on simpler deployments and L2 services. • Table of Contents
•

It is understandable why the industry started looking at simpler VPN schemes like L2VPNs to Metro Ethernet avoid many of the L3VPN complexities and to create a model in which simpler services like By Sam Halabi LAN Service (TLS) can be deployed with less operational overhead. Transparent In an L2 service, the carrier offers its customers the ability to "transparently" overlay their own Publisher: Cisco Press networks on top of the carrier's network. The customer of a carrier could be an ISP that offers Pub Date: October 01, 2003 Internet services and purchases last-mile connectivity from the carrier, or an enterprise ISBN: 1-58705-096-X customer that uses the carrier's backbone to build the enterprise WAN while still controlling its Pages: 240 internal IP routing.

Index

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

L2 Ethernet Services over an IP/MPLS Network
The inherent properties of an IP/MPLS network mitigate most of the scalability issues by design. IP and MPLS have been widely deployed in large service provider networks, and these protocols have been fine-tuned over the years to offer high levels of stability and flexibility. Table 4-1 • Table of Contents shows a brief comparison of the merits of IP/MPLS versus L2 Ethernet networks.
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Metro Ethernet BySam Halabi

Index

Publisher: Cisco Press

Table 4-1. Comparing Ethernet and IP/MPLS
Ethernet No signaling Blocked ports via Spanning Tree Protocol IP/MPLS LDP, RSVP-TE, and so on Yes, via routing protocols and Time To Live

Pub Date: October 01, 2003

Feature ISBN: 1-58705-096-X
Pages: 240 Signaling

Loop-free topology

User and service VLAN ID space limited Label space more scalable The definitive guide to Enterprise and Carrier Metro Ethernet applications. identification Traffic engineering (TE) No TE RSVP-TE Discover the latest developments in metro networking, Ethernet, and MPLS services and Restoration Via STP Backup path, MPLS fast reroute what they can do for your organization Address aggregation No aggregation for MAC Yes, via classless interdomain Learn from the easy-to-read format that enables networking professionals of all levels to addresses routing understand the concepts Segmenting thethe L2 Ethernet network with IP/MPLS creates an L2 Ethernet at the Sam metro Gain from experience of industry innovator and best-selling Ciscodomain Press author, access and an IP/MPLS metro edge/core and WAN backbone capable of carrying the L2 services. Halabi, author of Internet Routing Architectures As you will see in this chapter, the closer the IP/MPLS network gets to the customer, the more Metro networks scalable the service will emerge becomes; ashowever, the next area it introduces of growth more for the complications. networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The exercise of always deploying Ethernet L2 services becomes one of balance between the L2 Ethernet metro has been a challenging environment for delivering data services because it has simplicity its scalability shortfalls and the L3availability IP/MPLS scalability its complexity been built and to handle the stringent reliability and needs forand voice. Carriers will have to shortfalls. First, it helps to compare andthe contrast that IP/MPLS offers over flat L2 go through fundamental shifts to equip metrothe for benefits next-generation data services demanded networks. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to You seen so farservices. in this book two extremes: one with an MPLS L3VPN service and one with offerhave enhanced data an all-L2 Ethernet service. In this chapter, you see the hybrid model that falls in between. Figure 4-6 shows how from an IP/MPLS domain can create a level of hierarchy that allows the L2 services to Metro Ethernet Cisco Press looks at the deployment of metro data services from a holistic be confined to the access/edge network. There could be either an L2 access with IP/MPLS edge view. It describes the current metro, which is based on TDM technology, and discusses the and core or challenges an L2 access and edge IP/MPLS core. the metro to address data services. drivers and carriers will with face in transforming Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Figure 4-6. Hybrid L2 and IP/MPLS Metro to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet

Table of Contents Index

By Sam Halabi edge/core network limits the L2 domains to the access or access/edge side and The IP/MPLS provides a scalable vehicle to carry the L2 services across.

The L2 Ethernet service across an IP/MPLS cloud can be a point-to-point (P2P) or multipoint-toPub Date: October 01, 2003 multipoint (MP2MP) service. This is very similar to the Metro Ethernet Forum (MEF) definitions of ISBN: 1-58705-096-X an Ethernet Line Service (ELS) and Ethernet LAN Service (E-LAN). The following associates the Pages: 240 service with the different methods to deliver it: P2P Ethernet Service— Comparable to ELS, delivered via: The definitive guide to Enterprise and Carrier Metro Ethernet applications. - L2TPv3 over an IP network - Ethernet over MPLS, also known as draft-martini in reference to the author of the Discover the latest developments in metro networking, Ethernet, and MPLS services and original draft what they can do for your organization MP2MP Ethernet Service— Comparable to E-LAN, delivered via VPLS Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Before getting into more details of the different mechanisms to deploy P2P and MP2MP L2 services, it helps to understand the packet leased-line concept, which is also referred to as Gain from the experience of industry innovator and best-selling Cisco Press author, Sam pseudowire (PW), as explained next. Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The Pseudowire Concept The metro has always been a challenging environment for delivering data services because it has been built to Engineering handle the stringent reliability availability for Carriers will have to The Internet Task Force (IETF) and has defined the needs concept ofvoice. a pseudowire. An Ethernet go through fundamental shifts to equip the metro for next-generation data services demanded PW allows Ethernet/802.3 protocol data units (PDUs) to be carried over a PSN, such as an by enterprise customers and consumers. This is or not only a technology but also a existing shift in the IP/MPLS network. This allows service providers enterprise networksshift, to leverage an operational and business model that will allow the incumbent carriers to transform the metro to IP/MPLS network to offer Ethernet services. offer enhanced data services. You could set up the PW via manual configuration or a signaling protocol such as BGP or LDP. Metro Ethernet from Cisco Press looks at the The PW may operate over an MPLS, IPv4, or deployment IPv6 PSN. of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers willEthernet face in transforming metro to endpoints. address data services. An Ethernet PW emulates a single link betweenthe exactly two The PW terminates a logical port within the PE. This port provides an Ethernet MAC service that delivers Metro Ethernetpacket discusses adoption ofthe metro Ethernet services and port how in that has led carriers each Ethernet thatthe is received at logical port to the logical the corresponding to the delivery of metro data services. With a changing mix of transport technologies, the book PE at the other end of the PW. Before a packet is inserted into the PW at the PE, the packet can then examines current and emerging trends, and delves into the role of virtual private networks go through packet processing functions that may include the following: (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Stripping Tag stacking or swapping Bridging

Publisher: Cisco Press

L2 encapsulation Policing Shaping Figure 4-7 shows a reference model that the IETF has adopted to support the Ethernet PW emulated services. As Figure 4-7 shows, multiple PWs can be carried across the network inside a • Table of Contents bigger tunnel called the PSN tunnel. The PSN tunnel is a measure to aggregate multiple PWs into • Index a single tunnel across the network. The PSN tunnel could be formed using generic routing Metro Ethernet (GRE), Layer 2 Tunneling Protocol (L2TP), or MPLS and is a way to shield the encapsulation internals of the network, such as the P routers, from information relating to the service provided By Sam Halabi by the PEs. In Figure 4-7, while the PE routers are involved in creating the PWs and mapping the L2 service to the PW, the P routers are agnostic to the L2 service and are passing either IP or Publisher: Cisco Press MPLS packets from one edge of the backbone to the other.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 4-7. Creating Pseudowires

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to The following sections describe the different mechanisms used to deliver P2P and MP2MP L2 go through fundamental shifts to equip the metro for next-generation data services demanded Ethernet service over MPLS, starting with L2TPv3. You then learn more about Ethernet over by enterprise customers and consumers. This is not only a technology shift, but also a shift in the MPLS—draft-martini and VPLS. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. MetroSetup PW Ethernet Via from L2TPv3 Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the L2 metro to address data services. L2TP provides a dynamic tunneling mechanism for multiple circuits across a packet-oriented data network. L2TP was originally defined as a standard method for tunneling the Point-to-Point Metro Ethernet discusses the adoption of metro Ethernet and that led carriers Protocol (PPP) and has evolved as a mechanism to tunnelservices a number ofhow other L2 has protocols, to the delivery of metro data services. With a changing mix of transport technologies, book including Ethernet. L2TP as defined in RFC 2661, Layer 2 Tunneling Protocol (L2TP), is the referred then examines current and emerging trends, and delves into the role of virtual private networks to as L2TPv2. L2TPv3 is an extension of that protocol that allows more flexibility in carrying L2 (VPN), virtual private local area networks (VLAN), virtual private LAN services traffic of protocols other than PPP. Notable differences between L2TPv2 and L2TPv3 are (VPLS), the separation engineering, and MPLS and Generalized MPLS (GMPLS). all PPP-related attributes and references and the transition from a 16-bit Session ID and Tunnel ID to a 32-bit Session ID and Control Connection ID, offering more scalability in deploying L2 tunnels. With L2TPv3 as the tunneling protocol, Ethernet PWs are actually L2TPv3 sessions. An L2TP control connection has to be set up first between two L2TP control connection endpoints (LCCEs)

at each end, and then individual PWs can be established as L2TP sessions. The provisioning of an Ethernet port or Ethernet VLAN and its association with a PW on the PE triggers the establishment of an L2TP session. The following are the elements needed for the PW establishment: PW type— The type of PW can be either Ethernet port or Ethernet VLAN. The Ethernet port Table the of Contents type allows connection of two physical Ethernet ports, and the Ethernet VLAN indicates Index that an Ethernet VLAN is connected to another Ethernet VLAN. Each PW is associated with a PW ID that identifies the actual PW.

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Metro Ethernet

ID— BySamPW Halabi

The entire Ethernet frame without the preamble or FCS is encapsulated in L2TPv3 and is sent as Publisher: Cisco Press a single packet by the ingress side of the L2TPv3 tunnel. This is done regardless of whether an Pub Date: 01, 2003 802.1Q tag October is present in the Ethernet frame. For a PW of type Ethernet port, the egress side of ISBN: 1-58705-096-X the tunnel simply de-encapsulates the Ethernet frame and sends it out on the appropriate interface Pages: without 240 modifying the Ethernet header. The Ethernet PW over L2TP is homogeneous with respect to packet encapsulation, meaning that both ends of the PW are either VLAN tagged or untagged; however, once the packet leaves the PW, a Native Service Processing (NSP) function within the PE can still manipulate the tag information. For VLAN-to-VLAN connectivity, for example, the egress NSP function may rewrite the VLAN tag if a tag replacement or swapping function is needed. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

NOTE

Learn from the easy-to-read format that enables networking professionals of all levels to The preamble is concepts a pattern of 0s and 1s that tells a station that an Ethernet frame is understand the coming. FCS is the frame check sequence that checks for damage that might have occurred tothe theexperience frame in transit. These fields are not best-selling carried inside the Press PW. author, Sam Gain from of industry innovator and Cisco Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will Figure 4-8a shows L2TP control connection formed between PE1 andand PE2. Over that customers. connection represent major an shift in how data services are offered to businesses residential two orhas L2TPV3 sessions formed. The two sessions are of type Ethernet VLAN, whichit has The PWs metro always been aare challenging environment for delivering data services because means that the PW represents a connection between two VLANs. For 1, VLANwill 10 has been built to handle the stringent reliability and availability needs forsession voice. Carriers have to been left intact on both sides. session 2, the NSP within PE2 rewrites VLAN ID 20 to go through fundamental shiftsFor to equip the metro for function next-generation data services demanded VLAN ID 30 before delivering the packet on the segment. by enterprise customers and consumers. This is local not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Figure 4-8. Ethernet over L2TPV3 Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Ethernet over MPLS—Draft-Martini
You have seen in the previous section how an Ethernet packet can be transported using an L2TPv3 tunnel guide over an IP network. The IETF has also defined applications. a way to carry L2 traffic over an The definitive to Enterprise and Carrier Metro Ethernet MPLS network. This includes carrying Ethernet over MPLS (EoMPLS), Frame Relay, and ATM. This is also referred to as "draft-martini" encapsulation in reference to the author of the original Discover the latest developments in metro networking, services and Internet draft that defined Layer 2 encapsulation over MPLS. Ethernet, With this and typeMPLS of encapsulation, what they can do for your organization PWs are constructed by building a pair of unidirectional MPLS virtual connection (VC) LSPs between the two PE endpoints. One VC-LSP is for outgoing traffic, and the other is for incoming Learn from the are easy-to-read that enables networking professionals levels to traffic. The VC-LSPs identified format using MPLS labels that are statically assigned of or all assigned understand the concepts using the Label Distribution Protocol (LDP). Gain from the experience of industry and best-selling Cisco Press author, EoMPLS uses "targeted" LDP, which allowsinnovator the LDP session to be established between theSam ingress Halabi, author of Internet Routing Architectures and egress PEs irrespective of whether the PEs are adjacent (directly connected) or nonadjacent (not directly connected). The following section explains the mechanism of encapsulating the Metro networks will emerge as the next area of growth for the networking industry and will Ethernet frames over the MPLS network and shows two scenarios of using LDP to establish PWs represent a major shift in how data services are offered to businesses and residential customers. between directly connected and non-directly connected PEs. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Ethernet Encapsulation by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Ethernet encapsulation is very similar to what was described in the "PW Setup Via L2TPv3" offer enhanced data services. section, but a different terminology is introduced. The entire Ethernet frame without any Metro Ethernet from Cisco Pressas looks at the deployment ofPW. metro data a holistic preamble or FCS is transported a single packet over the The PW services could befrom configured as view. describes the current metro, which is based on TDM technology, and discusses the one ofIt the following: drivers and challenges carriers will face in transforming the metro to address data services. mode— In raw mode, the assumption is that the PW represents a virtual connection MetroRaw Ethernet discusses the adoption of metro Ethernet services and how that has led carriers between Ethernet ports. What goes one side goes the other side. The traffic to the deliverytwo of metro data services. With a in changing mix of out transport technologies, the book could be tagged or untagged and comesand out delves on the into egress then examines current and emerging trends, theuntouched. role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Taggedand mode— tagged mode, the assumption engineering, MPLSIn and Generalized MPLS (GMPLS). is that the PW represents a connection between two VLANs. Each VLAN is represented by a different PW and is switched differently in the network. The tag value that comes in on ingress might be overwritten on the egress side of the PW. The raw and tagged modes are represented in Figure 4-9.

Figure 4-9. Martini Tunnel Modes

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 4-9 shows that PE1 has established a PW of type raw with PE2 over which all traffic coming in on port 1 is mapped. As such, the traffic comes out as-is at the other end of the PW on PE2 port 1. Also, PE1 has defined on port 2 two PWs of type tagged. The first PW maps VLAN 20 on PE1 port 2 guide and connects it to VLAN 20 on PE2 port 1, and the second PW maps VLAN 30 on The definitive to Enterprise and Carrier Metro Ethernet applications. PE1 port 2 and maps it to VLAN 30 on PE2 port 2. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do Unit for your organization Maximum Transmit Learn from the easy-to-read format that enables networking professionals of all levels to Both understand ends of the PW agree on their maximum transmission unit size to be transported over the must concepts the PSN, and the network must be configured to transport the largest encapsulation frames. If MPLSGain is used asthe theexperience tunneling protocol, the addition of the MPLS shim layerPress increases theSam frame from of industry innovator and best-selling Cisco author, size. If the vendor implementation doesArchitectures not support fragmentation when tunneling the Ethernet Halabi, author of Internet Routing service over MPLS, care must be taken to ensure that the IP/MPLS routers in the network are adjusted to the largest maximum transmission Metro networks will emerge as the next area of unit. growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Frame Reordering go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the The IEEE 802.3 requires that frames from the same conversation be delivered in sequence. operational and business model that will allow the incumbent carriers to transform the metro to Because the frames are now encapsulated inside PWs, the PW must be able to support frame offer enhanced data services. reordering. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Using with Directly Connected PEs drivers LDP and challenges carriers will face in transforming the metro to address data services. Metro discusses the adoption metro Ethernet services andbetween how that has led carriers FigureEthernet 4-10 shows how martini tunnelsof can be established using LDP two directly to the delivery of metro data services. With a changing mix of transport technologies, the book connected PEs, such as PE1 and PE2. First, an LDP session needs to be established between the then examines current and emerging trends, and delves into the role of virtual private networks two PEs. Once the LDP session has been established, all PWs are signaled over that session. In (VPN), virtual you private area networks (VLAN), virtual privatePW LAN services (VPLS), traffic this example, can local see the establishment of one bidirectional via two unidirectional VCengineering, andVC-LSPs MPLS and Generalized MPLS (GMPLS). LSPs. Once both are established, the PW is considered operational. PE2 assigns label 102 and sends it to PE1 to be used for propagating traffic from PE1 to PE2. In turn, PE1 assigns label 201 and sends it to PE2 to be used for propagating traffic from PE2 to PE1. The label is pushed into the data packet before transmission, and it indicates to the opposite endpoint what to expect regarding the encapsulated traffic. Remember that this type of encapsulation is used to tunnel not only Ethernet but other types of traffic such as ATM, Frame Relay, and Circuit

Emulation traffic. The VC label gives the opposite side an indication of how to process the data traffic that is coming over the VC-LSP.

Figure 4-10. LDP Between Directly Connected PEs

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization The VC information is carried in a label mapping message sent in downstream unsolicited mode with a new type forwarding equivalency class element defined as follows (refer Learn from of the easy-to-read format that enables networking professionals of to allFigure levels 4to 11): understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam VC Type— A value that represents whether the VC is of type Frame Relay data-link Halabi, author of Internet Routing Architectures connection identifier (DLCI), PPP, Ethernet tagged or untagged frames, ATM cell, Circuit Emulation, andemerge so on. as the next area of growth for the networking industry and will Metro networks will represent a major shift in how data services are offered to businesses and residential customers. PW ID oralways VC ID— A connection ID that together for with the PW type identifies particular The metro has been a challenging environment delivering data services a because it has PW (VC). For P2P tunnels, the VC ID gives an indication of a particular service. will see been built to handle the stringent reliability and availability needs for voice. Carriers You will have to in the fundamental next section that in to the context an MP2MP VPLS service,data the VC ID is indicative of go through shifts equip the of metro for next-generation services demanded a LAN. customers and consumers. This is not only a technology shift, but also a shift in the by enterprise operational and business model that will allow the incumbent carriers to transform the metro to Group ID— Represents a group of PWs. The Group ID is intended to be used as a port offer enhanced data services. index or a virtual tunnel index. The Group ID can simplify configuration by creating a group forCisco all PWs that belong to the same group, such as anservices Ethernet portacarrying Metromembership Ethernet from Press looks at the deployment of metro data from holistic multiple PWs. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Interface Parameters— A field that is used to provide interface-specific parameters, such the interface maximum transmission unit. Metroas Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current Figure and 4-11. emerging LDP trends, Forwarding and delves into Equivalency the role of virtual Class private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet

Table of Contents Index

MPLS BySam PWs Halabiare formed using two unidirectional VC-LSPs, which means that for each PW that is established from ingress to egress, a "matching" PW needs to be established between egress and ingress with the same PW ID and PW type.
Publisher: Cisco Press Pub remainder Date: October of 01,this 2003book, the terms PW and VC-LSP are used interchangeably, but In the ISBN: 1-58705-096-X remember that a PW is formed of two unidirectional VC-LSPs, one inbound and one outbound. Pages: 240

Non-Directly Connected PEs
If the PEs are not directly connected, the PE-to-PE traffic has to traverse the MPLS backbone The definitive guide toThese Enterprise and Carrier Metro Ethernet applications. across P core routers. routers do not need to get involved with the different services offered at the edge and are concerned only with transporting the traffic from PE to PE. To hide the information from the P routers, LSP tunnels are constructed between the different PEs using Discover the latest developments inshare metro networking, and MPLS and targeted LDP, and the different PWs can these tunnels.Ethernet, The construction of services the LSP tunnels what they can do for your organization does not relate to the Ethernet MPLS service whatsoever. These tunnels can be constructed via different methods, such as GRE, L2TP, or MPLS. If constructed via MPLS, a signaling protocol Learn from the easy-to-read format that enables networking professionals of all levels to such as RSVP-TE can be constructed to traffic-engineer these LSP tunnels across the network understand the concepts (RSVP-TE is explained in Chapter 6. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam InFigure 4-12, an LSP tunnel, called a packet-switched network (PSN) tunnel LSP, is Halabi, author of Internet Routing Architectures constructed between PE1 and PE2, and the PW is carried across that tunnel. The PSN tunnel LSP is constructed by having PE1as push tunnel label that gets from PE1 to PE2. The PSN Metro networks will emerge the a next area of growth for the the packets networking industry and will tunnel label is pushed on top of the VC label, which gives the other side an indication of how to represent a major shift in how data services are offered to businesses and residential customers. process the traffic. The P routers do not see the VC label and are only concerned with switching The metro has always been a challenging environment for delivering data services because it has the traffic the PE routers reliability irrespective of availability the service needs (indicated by the VC labels) been built between to handle the stringent and for voice. Carriers will that haveis to carried. The following describes the process of transporting a packet from ingress PE to egress go through fundamental shifts to equip the metro for next-generation data services demanded PE: by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced services. 1. When PE1 data sends a Layer 2 PDU to PE2, it first pushes a VC label on its label stack and then a PSN tunnel label. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current which is based on TDM technology, 2. As shown in Figure 4-12,metro, a targeted LDP session is formed between and PE1 discusses and PE2. the drivers and challenges carriers will face in transforming the metro to address data services. 3. PE2 gives PE1 label 102 to be used for traffic going from PE1 to PE2 (the same scenario Metrohappens Ethernet discusses thedirection). adoption of metro Ethernet services and how that has led carriers in the reverse to the delivery of metro data services. With a changing mix of transport technologies, the book then and emerging role ofpushed virtual on private 4. examines Label 102 current is pushed by PE1, andtrends, then a and PSN delves tunnel into LSP the label 5 is top. networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS andupper Generalized MPLS (GMPLS). 5. The P routers use the label to switch the traffic toward PE2. The P routers do not have visibility to the VC labels. 6. The last router before PE2 performs a penultimate hop popping function to remove the upper label before it reaches PE2. Penultimate hop popping is a standard MPLS function that alleviates the router at the end of the LSP (PE2 in this case) from performing a

6.

popping function and examining the traffic beneath at the same time. PE2 receives the traffic with the inner label 102, which gives an indication of what is expected in the PW.

Figure 4-12. LDP Between Non-Directly Connected PEs

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. So far you have seen a P2P L2 service over MPLS. Next, MP2MP is discussed when a LAN is Discover the latest developments in metro networking, Ethernet, and MPLS services and emulated over MPLS using VPLS. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Virtual Private LAN Service Gain from the experience of industry innovator and best-selling Cisco Press author, Sam With Virtual Service, an L2VPN emulates a LAN that provides full learning and Halabi, Private author LAN of Internet Routing Architectures switching capabilities. Learning and switching are done by allowing PE routers to forward Ethernet frameswill based on learning the MAC addresses end stations that industry belong to the VPLS. Metro networks emerge as the next area of growth of for the networking and will VPLS allows an enterprise customer to be in full control of its WAN routing policies by running represent a major shift in how data services are offered to businesses and residential customers. the service transparently over a private or public IP/MPLS backbone. VPLS because services are The routing metro has always been a challenging environment for delivering data services it has transparent to higher-layer protocols and use L2 emulated LANs to transport any type of have traffic, been built to handle the stringent reliability and availability needs for voice. Carriers will to such as IPv4, IPv6, MPLS, IPX, to and so on. go through fundamental shifts equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the VPLS is flexible emulates LAN, but the by doing so it has all the of Ethernet operational and because businessitmodel thata will allow incumbent carriers to limitations transform the metro to protocols, including MAC addresses, learning, broadcasts, flooding, and so on. The difference offer enhanced data services. between VPLS and EoMPLS is that VPLS offers an MP2MP model instead of the previously discussed P2P model with L2TPv3 or EoMPLS using martini Metro Ethernet from Cisco Press looks at the deployment oftunnels. metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the With VPLS, CEs arecarriers connected PEs that are VPLS-capable. The can participate in one drivers and the challenges willto face in transforming the metro to PEs address data services. or many VPLS domains. To the CEs, the VPLS domains look like an Ethernet switch, and the CEs can exchange information with each other as if they wereservices connected via a LAN. This led also Metro Ethernet discusses the adoption of metro Ethernet and how that has carriers facilitates the IP the WAN links, because the VPLS could be formed with the a single to the delivery ofnumbering metro dataof services. With a changing mix of transport technologies, bookIP subnet. Separate L2 broadcast domains are maintained a per-VPLS byprivate PEs. Such then examines current and emerging trends, and delveson into the role ofbasis virtual networks domains are then mapped tunnels in the service provider network. These tunnels either (VPN), virtual private local into area networks (VLAN), virtual private LAN services (VPLS),can traffic be specific to and a VPLS (for example, IP tunnels) or shared among several VPLSs (for example, engineering, MPLS and Generalized MPLS (GMPLS). with MPLS LSPs). The PE-to-PE links carry tunneled Ethernet frames using different technologies such as GRE, IPSec, L2TP, MPLS, and so on. Figure 4-13 shows a typical VPLS reference model.

Figure 4-13. VPLS Reference Model
[View full size image]

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive toMPLS Enterprise and Carrier Metro Ethernet As Figure 4-13 guide shows, LSP tunnels are created between applications. different PEs. These MPLS tunnels can be shared among different VPLS domains and with other services such as EoMPLS tunnels, Layer 3 MPLS VPN tunnels, and so on. The PE routers are configured to be part of one, many, or Discover the latest developments in participating metro networking, Ethernet, and MPLS services and no VPLS, depending on whether they are in a VPLS service. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

NOTE

Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing The access network connecting the Architectures CEs to the PEs could be built with Ethernet technology or with next-generation SONET/SDH running Ethernet framing over the Metro networks will emerge as the next area of growth for the networking industry and will Generic Framing Protocol (GFP) or any logical links such as ATM PVCs or T1/E1 TDM or represent a major shift in how data services are offered to businesses and residential customers. any virtual or physical connections over which bridged Ethernet traffic is carried. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is notof only a technology The following sections discuss the different aspects a VPLS model: shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. VPLS requirements Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view.Signaling It describes current metro, which is based on TDM technology, and discusses the thethe VPLS service drivers and challenges carriers will face in transforming the metro to address data services. VPLS encapsulation Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Creating loop-free topology to the deliverya of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks MAC address learning (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). MAC address withdrawal Unqualified versus qualified learning Scaling the VPLS service via hierarchical VPLS (HVPLS)

Autodiscovery Signaling using BGP versus LDP Comparing the Frame Relay and MPLS/BGP approaches L2VPN BGP model
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BySam Halabi

Table of Contents Frame Relay access with MPLS edge/core Index

Metro Decoupled Ethernet

Transparent LAN Service (DTLS)

VPLS Requirements Publisher: Cisco Press
Following are the basic requirements of a VPLS service: ISBN: 1-58705-096-X
Pages: 240 Pub Date: October 01, 2003

Separation between VPLS domains— A VPLS system must distinguish different customer domains. Each customer domain emulates its own LAN. VPLS PEs must maintain a separate virtual switching instance per VPN. MAC learning— VPLS should capable of learning forwarding based on MAC The definitive guide to A Enterprise andbe Carrier Metro Ethernetand applications. addresses. The VPLS looks exactly like a LAN switch to the CEs. Switching— A VPLS switch should able networking, to switch packets between different tunnels Discover the latest developments inbe metro Ethernet, and MPLS services and based on MAC VPLS switch should also be able to work on 802.1p/q tagged what they can addresses. do for your The organization and untagged Ethernet packets and should support per-VLAN functionality. Learn from the easy-to-read format that enables networking professionals of all levels to Flooding— A VPLS should be able to support the flooding of packets with unknown MAC understand the concepts addresses as well as broadcast and multicast packets. Remember that with Ethernet, if a Gain from switch does the not experience recognize of a destination industry innovator MAC address, and best-selling it should flood Ciscothe Press traffic author, to all Sam ports Halabi,aauthor within certain of VLAN. Internet With Routing the VPLS Architectures model shown in Figure 4-13, if a VPLS-capable device receives a packet from VPLS A with an unknown MAC destination address, the VPLS device Metro networks will emerge as the areaVPLS-capable of growth for devices the networking industryin and willA. should replicate the packet to next all other that participate VPLS represent a major shift in how data services are offered to businesses and residential customers. The metro Redundancy has always and been failure a challenging recovery— environment The VPLS should for delivering be able data to recover services from because network it has been failure built to to handle ensure the high stringent availability. reliability The service and availability should be needs restored for voice. around Carriers an alternative will have to go through path, and fundamental the restoration shifts to time equip should the be metro lessfor than next-generation the time the CEs data or services customer demanded L2 control by enterprise protocols customers need to detect and consumers. the failure of This the isVPLS. not only The afailure technology recovery shift, and but redundancy also a shift of in the operational MPLS depends and business on how model fast that MPLS will paths allow can the be incumbent restored in carriers case ofto a transform failure andthe how metro fast the to offer network enhanced can data stabilize. services. Chapter 6 discusses MPLS fast restoration. MetroProvider Ethernet edge from Cisco signaling— Press looks In addition at the deployment to manual configuration of metro data methods, services VPLS from a should holistic view.provide It describes a way the to current signal between metro, which PEs to isauto-configure based on TDM and technology, to inform and thediscusses PEs of the drivers membership, and challenges tunneling, carriers and will other face in relevant transforming parameters. the metro Many to vendors address have dataadopted services. LDP as a signaling mechanism; however, there are some who prefer BGP as used in RFC 2547, MetroBGP/MPLS Ethernet discusses the adoption of metro Ethernet services and how that has led carriers VPNs . to the delivery of metro data services. With a changing mix of transport technologies, the book then examines VPLS membership current and discovery— emerging trends, The VPLS and control delves into plane the and role management of virtual private plane networks should (VPN), provide virtualmethods private local to discover area networks the PEs (VLAN), that connect virtual CEs private forming LAN a VPLS. services Different (VPLS), traffic engineering, mechanisms and MPLS can be and used Generalized to achieve MPLS discovery. (GMPLS). One method is via the use of BGP, as adopted in the L3VPN model. However, there is some disagreement in the industry on whether BGP implementations are appropriate, due to the complexity of BGP and the fact that it cannot signal a different label to each VPLS peer, as required by MAC learning. A proposal for using BGP promotes the use of block label distribution, as explained in the "DTLS—Decoupling L2PE and PE Functionality" section later in this chapter.

Interprovider connectivity— The VPLS domain should be able to cross multiple providers, and the VPLS identification should be globally unique. VPLS management and operations— VPLS configuration, management, and monitoring are very important to the success of the VPLS service. Customer SLAs should be able to be monitored for availability, bandwidth usage, packet counts, restoration times, and so on. The metrics that have been defined by the MEF regarding performance and bandwidth parameters apply to the VPLS service. Table should of Contents
Index

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Metro Ethernet

Signaling the VPLS Service BySam Halabi
Signaling with VPLS is the same as described in the section "Ethernet over MPLS—Draft-Martini," Publisher: Cisco Press with LDP using a forwarding equivalency class element. The main difference is that in the P2P Pub Date: October 01, 2003 martini tunnel, the VC ID is a service identifier representing a particular service on the Ethernet ISBN: 1-58705-096-X port, such as a different P2P VLAN. With VPLS, the VC ID represents an emulated LAN segment, Pages: 240 and its meaning needs to be global within the same provider and across multiple providers.

VPLS Encapsulation
The definitive guide is toderived Enterprise and Carrier Metro Ethernet applications. VPLS encapsulation from the martini encapsulation used for a P2P EoMPLS service. The packet is always stripped from any service-related delimiter that is imposed by the local PE. This ensures that the Ethernet packet that traverses a VPLS is always a customer Ethernet Discover the latest developments in metro networking, Ethernet, and MPLS services and packet. Any service delimiters, such as VLAN or MPLS labels, can be assigned locally at the what they can do for your organization ingress PE and stripped or modified in the egress PE. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

Creating a Loop-Free Topology
Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures The problem with having a VPLS domain emulate a LAN is that it can create the same circumstances that create a loop in a LAN. With L2 Ethernet networks, Spanning Tree Protocol is Metro networks will emerge as the next area of growth for the networking industry and will used to prevent loops caused by the L2 flooding mechanism. In the case of VPLS, the same represent a major shift in how data services are offered to businesses and residential customers. scenario could happen as illustrated in Figure 4-14. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Figure L2 Loops go through fundamental shifts to equip the 4-14. metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to [View full size image] offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X

InFigure 4-14, three LSP tunnels connect PE1, PE2, and PE3. VPLS A is emulating a LAN that is carried over these LSP tunnels. If CE1 sends a packet with a destination MAC address, say 080002001234, that is unknown by PE1, PE1 has to flood, or replicate, that packet over the two tunnels connecting it to PE2 and PE3 that participate in the same VPLS. If PE2 does not know of the destination as well, it sends the packet to PE3 and CE2. In the same manner, if PE3 does not The definitive guide to Enterprise and Carrier Metro Ethernet applications. know of the destination, it sends the packet to PE1 and CE3, and the loop continues. To break the loop, Spanning Tree Protocol (STP) has to run on the PEs, and in the same way that Ethernet frames are tunneled over the MPLS LSPs, STP BPDUs also have to be tunneled. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization To avoid the deployment of spanning trees, a full mesh of LSPs needs to be installed between the PEs, and each PE must support a split-horizon scheme wherein the PE must not forward traffic Learn from the easy-to-read format that enables networking professionals of all levels to from one PW to another in the same VPN. This works because each PE has direct connectivity to understand the concepts all other PEs in the same VPN. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam InFigure 4-15, a full mesh of tunnel LSPs and VC-LSPs (which are used to demultiplex the Halabi, author of Internet Routing Architectures service over the tunnel LSPs) has been configured between all PEs. A PE receiving a packet over a VC-LSP cannot forward that to area otherof VC-LSPs. PE1 receives an Ethernet packet with an Metro networks will emerge aspacket the next growth for the networking industry and will unknown destination and replicates that packet over the three VC-LSPs that connect it to PE2, represent a major shift in how data services are offered to businesses and residential customers. PE3, and PE4. Because there is a full mesh, PE2, PE3, and PE4 assume that the same packet The metro has always been a challenging environment for delivering data services because it has they has already been sent by the other PEs and thus do not replicate it. This prevents been received built to handle the stringent reliability and availability needs for voice. Carriers will have to loops from taking place. Requiring a full mesh of LSPs becomes an issue if the PE functionality go through fundamental shifts to equip the metro for next-generation data services demanded is moved closer customers into the access cloud, such as inis the basement of multitenant (MTU) buildings. by enterprise and consumers. This not only a technology shift, unit but also a shift in the This would create an explosion of an LSP mesh that does not scale. The section "Scaling the to operational and business model that will allow the incumbent carriers to transform the metro VPLS Service Via Hierarchical offer enhanced data services. VPLS" later in this chapter explains how such a scenario is solved. Metro Ethernet fromFigure Cisco Press looksAvoiding at the deployment ofVia metro data services from a holistic 4-15. Loops Full Mesh view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet [View full size image]services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Pages: 240

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

In some cases, an enterprise customer can create a backdoor loop by connecting multiple sites directly via an L2 connection. To avoid loops, STP can be run on the CEs, and the STP BPDUs are tunneled over the MPLS cloud like any other data packets. This is shown in Figure 4-16. The definitive guide to Enterprise Figure and Carrier 4-16.Metro Backdoor Ethernet Loops applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and [View full size image] what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the In Figure 4-16, CE2 and CE3 have a direct L2 connection, creating a loop, because traffic operational and business model that will allow the incumbent carriers to transform the metro to between CE2 and CE3 can traverse two different paths: the direct connection and the MPLS offer enhanced data services. cloud. If the customer runs STP between the two CEs, STP BPDUs can be tunneled over the MPLS cloud, causing the loop to break. In case MPLS connection or the direct connection Metro Ethernet from Cisco Press looks at the the deployment of metro data services from afails, holistic traffic is switched over the remaining connection. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. So, there are many ways to create loops in an Ethernet L2 switched architecture. Some of these loops can be caused by the service provider equipment and some and by the enterprise Metro Ethernet discusses the adoption of metro Ethernet services how that has equipment led carriers itself. creates more data strain on the operation and management of these systems, when to the This delivery of metro services. With a changing mix of transport technologies, the book problems occur. Well-defined rules need to be set delves to indicate which L2 control are to be then examines current and emerging trends, and into the role of virtualPDUs private networks carried virtual over the provider network. This prevents finger-pointing the customer and (VPN), private local area networks (VLAN), virtual privatebetween LAN services (VPLS), traffic provider in case such as broadcast storms occur. engineering, andproblems MPLS and Generalized MPLS (GMPLS).

MAC Address Learning
In the P2P PW scenarios in which Ethernet packets come in on one side of the PW and come out

on the other side, MAC learning is not necessary. What goes in the tunnel comes out on the other end. VPLS operates in any-to-any MP2MP mode. This means that a PE is connected with multiple VC-LSPs to different PEs that participate in the multiple VPLS domains, and the PE needs to decide which LSPs to put the traffic on. This decision is based on destination MAC addresses that belong to a certain VPLS. It is unreasonable to assume that this function can be statically configured (although it could), because many MAC addresses would need to be mapped to many LSPs. MAC learning allows the PE to determine from which physical port or LSP a particular MAC address came. • Table of Contents
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Figure 4-17 shows an example of how MAC learning is achieved.
Metro Ethernet BySam Halabi

Index

Figure 4-17. MAC Learning

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will In Figure 4-17, PE1, PE2, PE3 establish pairs of VC-LSPs between each other as follows: represent a major shift inand how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle stringent reliability availability needs VC for label voice. Carriers will have to 1. Using LDP, PE2 the signals VC label 201 toand PE1, and PE1 signals 102 to PE2. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise and consumers. not only technology shift, but also a shift in the 2. A stationcustomers behind CE2, STA 2, with a This MACis address ofa 080002002222, sends a broadcast operational and business model that will allow the incumbent carriers to transform the metro to packet to destination MAC FFFFFFFFFFFF. PE2 recognizes that STA 2 belongs to VPLS A (via offer configuration enhanced data services. or other mechanism) and replicates the packet to the two VC-LSPs connected to PE1 and PE3 that also participate in VPLS A. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is inbound based onVC-LSP, TDM technology, and discusses the 3. When the packet comes to PE1 on PE1's it associates the MAC address of drivers and challenges carriers will face in the metro to address data services. STA 2 with the "outbound" VC-LSP in transforming the same VC-LSP pair that constitutes the PW between PE2 and PE1. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to4. the delivery of metro data services. With a changing mix of 080002002222, transport technologies, the book From then on, if PE1 receives a packet destined for MAC it automatically then examines current and emerging trends, and delves into the role of virtual private networks sends it on its outbound VC-LSP using label 201 (which was signaled by PE2). (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized (GMPLS). This process constitutes MAC learning onMPLS the VC-label side. Standard Ethernet MAC learning occurs on the Ethernet port side, where PE2, for example, associates MAC 080002002222 with its local Ethernet port or the VLAN it came on. This process continues until all PEs have learned all MAC addresses on their local ports/VLANs and across the MPLS cloud. Notice that PE1 signals two different labels to PE2 and PE3. In this example, PE1 signals label 102 to PE2 and 103 to PE3. This way, PE1 can distinguish inbound packets from PE2 and PE3.

MAC Address Withdrawal
L2 Ethernet switching includes a mechanism called MAC aging that lets MAC addresses be aged out of an Ethernet switch MAC table after a certain period of inactivity. In some cases, such as an MTU building that is dual-homed to two different Ethernet switches in the central office (CO), faster convergence can occur if a mechanism exists to age out (withdraw) or relearn MAC • Table of Contents addresses in a way that is faster than the traditional L2 MAC aging. The IETF has defined a MAC • Index type length value (TLV) field that can be used to expedite learning of MAC addresses as a result Metro Ethernet of topology change.
BySam Halabi

Publisher: Cisco Press Unqualified Versus Qualified Learning Pub Date: October 01, 2003 ISBN: 1-58705-096-X When a PE learns MAC addresses from the attached customers, these MAC addresses are kept in Pages: 240 a Forwarding Information Base (FIB). The FIB should keep track of the MAC addresses and on which PWs they were learned. This allows MAC addresses to be tracked by VPLS. This is different from the traditional MAC learning of Ethernet switches, where all MAC addresses are shared by a single customer. VPLS can operate in two learning modes, unqualified and qualified.

In unqualified learning, a customer VPLS is a port-based service where the VPLS is considered a The definitive guide to Enterprise and Carrier Metro Ethernet applications. single broadcast domain that contains all the VLANs that belong to the same customer. In this case, a single customer is handled with a single VPLS. On the other hand, qualified learning assumes a VLAN-based where each customer VLAN canEthernet, be treated as MPLS a separate VPLS and Discover the latest VPLS developments in metro networking, and services and as a separate broadcast domain. The advantage of qualified learning is that customer broadcast what they can do for your organization is confined to a particular VLAN. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

Scaling the VPLS Service Via Hierarchical VPLS

Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures The VPLS service requires a full mesh of VC-LSPs between the PE routers. This works adequately if the PE routerswill are emerge contained COs and the different customers are aggregated in these Metro networks as in the next area of growth for the networking industry and willCOs. In the case of MTU deployments, the PEs are deployed in the building basements where multiple represent a major shift in how data services are offered to businesses and residential customers. customers are aggregated. In this case, starting the VPLS service in the PE might cause The metro has always been a challenging environment for delivering data services because it has scalability there are many more buildingsneeds than COs. A fullCarriers mesh ofwill LSPs been built problems to handle because the stringent reliability and availability for voice. have to between all the buildings that participate in the VPLS service would cause an unmanageable LSP go through fundamental shifts to equip the metro for next-generation data services demanded deployment. For x PEs that are deployed, x * ( x – 1) / 2 bidirectional LSPs need to be deployed. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Remember that it takes twothat LSPs—one inbound and one outbound—to construct a metro to operational also and business model will allow the incumbent carriers to transform the bidirectional PW, which means that x * ( x – 1) unidirectional VC-LSPs need to be signaled. offer enhanced data services. Figure 4-18 shows a deployment in which the VPLS startsof in metro the basement of MTU buildings and Metro Ethernet from Cisco Press looks at the deployment data services from a holistic a full mesh of LSPs is required between PEs. This LSP explosion will cause an operational view. It describes the current metro, which is based on TDM technology, and discusses the nightmare. drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Figure 4-18. Full Mesh to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam For any "new" MTU building that is added to the network, the new MTU must be meshed to every Halabi, author of Internet Routing Architectures PE in the existing MTUs, which doesn't scale. Packets get flooded over all LSPs participating in a VPLS; if the MAC destination is the unknown, thisof puts a big load the MTU PE. Metro networks will emerge as next area growth for theon networking industry and will represent a major shift in how data services are offered to businesses and residential customers. A better approach for MTUs to create a hierarchical VPLS (HVPLS) model in which the MTU The metro has always been is a challenging environment for delivering data services because it PEs has establish access tunnels (spokes) to the CO and PEs, availability and the COneeds PEs (hubs) establish a full mesh. been built to handle the stringent reliability for voice. Carriers will have to This is shown in Figure 4-19. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent Figure 4-19. HVPLScarriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures The hierarchical model scales better, because a new MTU that is added to the network has to Metro networks will emerge as the next area of growth for the networking industry and will establish an LSP only with the local PE and does not need to establish LSPs with every other PE. represent a major shift in how data services are offered to businesses and residential customers. This is a major operational cost saving. The metro has always been a challenging environment for delivering data services because it has been to handle thefor stringent reliability availability needs voice. Carriers will have to Therebuilt are many flavors the MTU and the and CO PEs. The IETF has for adopted the following go through fundamental shifts to equip the metro for next-generation data services demanded terminology that is used in the rest of the chapter: by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer MTU-s— enhancedThis datais services. a PE that is placed in the MTU and is capable of doing MAC learning and L2 switching/bridging. This could be a pure L2 Ethernet switch, or an L2 Ethernet switch that Metrois Ethernet Cisco Press and looks at the deployment metro services from a holistic capable from of MPLS tagging forwarding but does of not havedata to do any IP routing. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers face of in IP transforming thebut metro to address data services. PE-r— This is a PE that is will capable routing/MPLS is not capable of MAC learning. This device can be placed in the MTU or the CO. This is basically an IP/MPLS router. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. a changing mix and of transport technologies, the book PE-rs— This a PE that is capable With of both L2 switching IP routing. then examines current and emerging trends, and delves into the role of virtual private networks The following explain two different scenarios used in service (VPN), virtual sections private local area networks (VLAN), virtual private LANprovider services deployments: (VPLS), trafficone for MTU-s deployments and Generalized the other forMPLS PE-rs. engineering, and MPLS and (GMPLS).

MTU Device Supports MAC Learning and L2 Switching (MTU-s)
In this scenario, the MTU-s is an L2 Ethernet switch that is capable of MAC learning and can do

switching based on MAC addresses. The MTU-s does all the normal bridging functions of learning and replications on all its ports, including the virtual spoke ports, which are the PWs that connect the MTU-s to the PE-rs. The ability of the MTU-s to do MAC learning and bridging simplifies the signaling between the MTU-s and the PE-rs at the CO, because the MTU-s can associate all the access ports belonging to the same VPLS with a single PW between the MTU-s and the PE-rs. This is better illustrated in Figure 4-20.
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Metro Ethernet BySam Halabi

Table of Contents Index

Figure 4-20. Sample MTU-s

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization InFigure 4-20, a service provider is offering a VPLS service to two customers via an MTU-s in Learn from easy-to-read that enables professionals ofon all the levels to the basement of the the building. The format MTU-s connects to anetworking PE-rs in the CO. Note that MTU-s, understand theports concepts two access Ethernet are assigned to VPLS A. These access ports are connected to CE11 and CE12, which both connect to the same customer. This scenario could occur if the same customer Gain from the experience industry innovator Cisco Press Samare has two different locations that of are in the same MTU and or a best-selling nearby building and all author, connections Halabi, author of Internet Routing Architectures serviced by the same MTU-s toward the CO. In this case, the MTU-s switches all traffic between CE11 and CE12 locally via regular L2 switching and switches traffic between CE11 and CE12 and Metro networks will emerge as the next area of growth for the networking industry and will the remote sites in VPLS A using a single PW between the MTU-s and the PE-rs in the CO. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Because the MTU-s also services VPLS B, the service provider has to assign a service delimiter to been built to handle the stringent reliability and availability needs for voice. Carriers will have traffic coming from VPLS A and VPLS B to differentiate between the two customers. Rememberto go through fundamental shifts to equip the metro for next-generation services demanded that this was discussed in Chapter 3, "Metro Ethernet Services," whichdata introduced the concept of by enterprise customers and consumers. This is not only a technology shift, but also a could shift in the using carrier VLAN IDs to differentiate between customer traffic. In this example, you set operational and business model that will allow the incumbent carriers to transform the metro to up the spoke in two ways: offer enhanced data services. MetroThe Ethernet from Ciscois Press looks at the deployment metro data services a holistic service provider using Q-in-Q to separate the of customer traffic on thefrom MTU-s and to view.indicate It describes the current metro, which is based on TDM technology, and discusses the to the PE-rs which traffic belongs to which VPLS. In this case, the service delimiter drivers challenges carriers will the metro to address data services. is and a carrier VLAN ID carried onface top in of transforming the customer's Ethernet packet. The customer traffic itself also could carry customer-specific VLAN tags; however, those tags are not seen by the Metroservice Ethernet discusses the adoption of metro Ethernet services and how that has led carriers provider. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual networks The service provider is using two martini EoMPLS PWs to carry traffic fromprivate the different (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic customers. In this case, the MPLS tag on top of the customer's Ethernet traffic is the service engineering, and MPLS and Generalized MPLS (GMPLS). delimiter recognized by the PE-rs. The decision of whether to use Q-in-Q or martini tunnels depends on the equipment the vendor uses in the MTU and the CO. In some cases, the MTU equipment doesn't support MPLS. In other cases, the MTU and CO equipment does not interoperate when using Q-in-Q. You should also remember that some Ethernet switch vendors support neither VLAN stacking on a per-customer

basis nor MPLS. You should not use such equipment in MTU deployments. Notice in this example that the PWs used between the MTU-s and the PE-rs have achieved multiple functions: The need for full PW mesh between the MTU-rs is eliminated. Only one PW is used per VPLS.
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Metro Ethernet BySam Halabi

Table of Contents Index overhead is minimized because fewer PWs are used. The signaling

MTU-s devices are only aware of the PE-rs they attach to and not to all MTU-s devices that participate in the VPLS. new MTU-s does not affect the rest of the network.

Publisher: Cisco Press An addition of a

Pub Date: October 01, 2003

The MTU-s MAC addresses both from the Ethernet customer connections in the building ISBN: learns 1-58705-096-X and from the spoke PWs. The MTU-s associates the MAC addresses per VPLS. If an MTU-s Pages: 240 receives a broadcast packet or a packet with an unknown destination MAC, the packet is flooded (replicated) over all the MTU-s physical or logical connections that participate within the VPLS. Note that there is one PW per VPLS on the spoke connection, so the packet is replicated only once per VPLS. The guide to the Enterprise and Carrier Metro Ethernet applications. The definitive MTU-s device and PE-rs device treat each spoke connection like a physical port on the VPLS service. On the physical ports, the combination of the physical port and VLAN tag is used to associate the traffic with a VPLS instance. On the spoke port, the VC label or carrier VLAN ID (for Discover the latest developments in metro networking, Ethernet, and MPLS services and Q-in-Q) is used to associate the traffic with a particular VPLS. L2 MAC address lookup is then what they can do for your organization used to find out which physical port the traffic needs to be sent on. Learn from the easy-to-read format that enables networking professionals of all levels to The PE-rs forms a full mesh of tunnels and PWs with all other PE-rs devices that are participating understand the concepts in the VPLS. A broadcast/multicast or a packet with an unknown MAC destination is replicated on all PWs connected to the PE-rs for a certain VPLS. Note that the PE-rsCisco can contain more VPLS Gain from the experience of industry innovator and best-selling Press author, Sam instances than the MTU-s, because the PE-rs participates in all the VPLSs of the MTU buildings Halabi, author of Internet Routing Architectures that are attached to it, while the MTU-s only participates in the VPLS of the customers in a particular building. theas MAC function is done twice: once at the MTU-s and another Metro networks will Also, emerge thelearning next area of growth for the networking industry and will time at the PE-rs. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through PE-rs Issues fundamental with MAC shifts Learning to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and model MAC that learning will allow the incumbent carriers to transform the metro to The fact that thebusiness PE-rs is doing raises concerns with service providers. The PE-rs offer enhanced data services. has to learn all the MAC addresses that exist in all VPLS instances it participates in. This could be in the hundreds of thousands of MAC addresses that need to be learned if the VPLS service is Metro Ethernet from Cisco Press looks at that the deployment of metro data services holistic delivering LAN connectivity between CEs are L2 switches. Remember that a from VPLSa emulates view. It describes the current metro, which is based on TDM technology, and discusses the a LAN service and learns all MAC addresses it hears from all stations connected to the LAN. If the drivers challenges carriers will face will in transforming the metro tobehind address data services. CEs areand L2 Ethernet switches, the VPLS learn all MAC addresses the Ethernet switch. Some of these concerns can be alleviated through different approaches: Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and trends, delves into the role of addresses virtual private networks If the CE equipment isemerging an IP router, the and VPLS learns only the MAC of the IP (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic router interfaces that are connected to the VPLS. MAC stations behind IP routers are engineering, MPLS and Generalized MPLS (GMPLS). hidden, and because IP routers route based on IP addresses and not MAC addresses. In this model, the MAC address space is very manageable. If the CEs are L2 switches, it is possible to use filtering mechanisms on the MTU-s to allow service for only a block of the customer's MAC addresses and not all of them. Filtering helps reduce the explosion of MAC addresses on the PE-rs; however, it adds more management

overhead for both the customer and the service provider. A different model can be used to allow the MTU-s to do MAC learning at the building and not to do MAC learning at the PE-rs. This model is called the Decoupled Transparent LAN Service (DTLS), which is explained later in this chapter in the section "DTLS—Decoupling L2PE and PE Functionality."
• Table of Contents

Non-Bridging Devices as Spokes • Index
Metro Ethernet

In some cases, existing IP routers are deployed as spokes. As previously described, the IETF BySam Halabi calls such a device a PE-r, to indicate routing functionality only. These routers are not capable of bridging and cannot switch packets based on MAC addresses. To offer an L2 service using the Publisher: Cisco Press PE-r, it is possible to create PWs between the PE-r and the CO PE-rs, where all the L2 switching Pub Date: October 01, functions are done at2003 the CO. This model creates more overhead, because unlike the MTU-s, ISBN: 1-58705-096-X where all access ports belonging to the same VPLS are mapped to a single PW, the PE-r requires that each Pages: access 240 port is mapped to its own PW. This is illustrated in Figure 4-21.

Figure 4-21. Spoke Device Is a Router
The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Figure 4-21 uses a PE-r as aaspoke. Note that VPLS A now requires two PWs—one CE11 and The metro has always been challenging environment for delivering data servicesfor because it has one for CE12—that belong to the same customer. For any traffic that be switched been built to handle the stringent reliability and availability needs for needs voice. to Carriers will have to between the two access ports same customer are connected to CE11 and demanded CE12, that go through fundamental shiftsof tothe equip the metro forthat next-generation data services traffic needs to be transported to the CO and at a the PE-rs. by enterprise customers and consumers. This switched is not only technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.

Dual-Homed MTU Devices

Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the It is possible to dual-home an MTU device to protect against the failure of a spoke or the failure drivers and challenges carriers will face in transforming the metro to address data services. of a PE-rs at the CO. Dual-home refers to connecting the MTU device via two separate spokes. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Figure 4-22 shows an MTU-s device that is dual-homed to the PR-rs at the CO via two PWs, one to the delivery of metro data services. With a changing mix of transport technologies, the book primary and one backup. To prevent an L2 loop in the network, the primary PW is active and then examines current and emerging trends, and delves into the role of virtual private networks passing traffic while the secondary PW is inactive. In this scenario, spanning tree is not needed, (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic because only a single PW is active at the same time. In normal operation, all PE-rs devices engineering, and MPLS and Generalized MPLS (GMPLS). participating in VPLS A learn the MAC addresses behind MTU-s via the primary PW connected to PE1-rs. The following two scenarios might take place: Failure of the primary PW— In this case the MTU-s immediately switches to the secondary PW. At this point the PE2-rs that is terminating the secondary PW starts learning

MAC addresses on the spoke PW. The speed of convergence in the network depends on whether MAC TLVs are used, as described in the "MAC Address Withdrawal" section earlier in this chapter. If the MAC address TLVs are used, PE2-rs sends a flush message to all other PE-rs devices participating in the VPLS service. As such, all PE-rs devices converge on PE2rs to learn the MAC addresses. If the MAC TLV is not used, the network is still operational and converges using the traditional L2 MAC learning and aging. During this slow convergence, the PE-rs devices slowly learn the MAC addresses in the network.
• •

Metro Ethernet BySam Halabi

Failure of the PE1-rs— In this case, all PWs that are terminated at PE1-rs fail, and the Index network converges toward PE2-rs.

Table of Contents

Figure 4-22. Dual-Homed MTU Device

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

Autodiscovery Gain from the experience of industry innovator and best-selling Cisco Press author, Sam
Halabi, author of Internet Routing Architectures Autodiscovery refers to the process of finding all the PEs that participate in a given VPLS. So far, Metro networks emerge as this the next area growth meaning for the networking industry and will this chapter has will assumed that function isof manual, that the network operator represent certain a majorPEs shift how data are offered to businesses and residential customers. dedicates toin belong to a services certain VPLS and configures that information on each PE The metro to has always challenging environment for delivering data services belonging the VPLS.been This a process can be configuration-intensive, especially with because a large it has been built handle the stringent reliability and availability needs for voice. Carriers will to number of to PEs, because manual configuration and deletion are needed every time a PE ishave added go or through fundamental shifts to equip the metro for next-generation data services to removed from the network. With autodiscovery, each PE discovers which otherdemanded PEs are part by the enterprise customers and consumers. This isare notadded only a to technology shift, but also a shift in the of same VPLS and discovers PEs when they or removed from the network. operational and business model will allow the incumbent carriers to the transform metro Different mechanisms have beenthat proposed by different vendors, such as use of the BGP, LDP, to or offer to enhanced services. This section elaborates on BGP and how it compares with LDP. DNS achieve data autodiscovery. Metro Ethernet from Cisco Press looks at the deployment of services from a holistic BGP uses the concept of extended communities to identify a metro VPLS. data PEs exchange information via view. It describes the current metro, which is basedpeering on TDM technology, and discusses the direct Internal BGP (IBGP) or External BGP (EBGP) or route reflectors. drivers and challenges carriers will face in transforming the metro to address data services. You saw at the beginning of this chapter that BGP is used with MPLS L3VPNs to achieve Metro Ethernet discusses the adoption metro Ethernet and how that has led carriers discovery of VPN information. A similarof approach is used services to achieve VPLS autodiscovery by to the delivery of metro data services. With a changing mix of transport technologies, the having the routes exchanged in BGP carry a VPN-L2 address. A VPN-L2 address contains abook route then examines current and emerging trends, and delves into the role of virtual private networks distinguisher (RD) field that distinguishes between different VPN-L2 addresses. Also, a BGP route (VPN), virtual private community local area networks (VLAN), virtual private LAN services (VPLS), traffic target (RT) extended is used to constrain route distribution between PEs. The RT is engineering, and MPLS and Generalized MPLS (GMPLS). indicative of a particular VPLS. Because a PE is fully meshed with all other PEs, it receives BGP information from all PEs. The PE filters out the information based on the route target and learns only information pertinent to the route targets (VPLSs) it belongs to.

Signaling Using BGP Versus LDP

In this chapter, you have learned about the use of LDP as a signaling mechanism to establish and tear down PWs between PEs. Some vendors have adopted BGP as a signaling mechanism because of its scalability and its ability to support VPLS deployment across multiple providers. This section presents a more detailed comparison of the use of LDP and BGP as a signaling mechanism and BGP. With LDP used as the signaling protocol, targeted LDP sessions are established between PE • Table of Contents peers. An LDP session is called "targeted" because it is set directly between two PEs that do not • Index have to be adjacent. These PEs exchange MPLS labels directly, and that information is hidden Metro from Ethernet the routers that exist on the path between these PE peers. You have seen that a full mesh ofSam By these Halabi peers between PEs is needed per VPLS. If all PE routers participate in every VPLS, a full mesh is needed between all PEs. Also, each PE needs to carry a separate FIB per VPLS, which increases the number Publisher: Cisco Press of FIBs per PE. However, it is possible to segment the network into PEs that have separate VPLS coverage, meaning that they do not serve a common set of VPLSs. In Pub Date: October 01, 2003 this case, the LDP mesh is needed only between the PEs covering a particular VPLS, and the ISBN: 1-58705-096-X signaling and the number of FIBs per PE are reduced.
Pages: 240

If all PEs participate in all VPLS instances, there is a full LDP mesh between all PEs, and each PE carries a FIB per VPLS, as shown in Figure 4-23, Part A. Figure 4-23, Part B, shows that three PEs participate in VPLS A and carry a VPLS A FIB (FIB A) while the other PEs carry a VPLS B FIB. Note that a full mesh between all PEs is not required. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Figure 4-23. LDP Signaling Options
Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Vendors proposing BGP as a signaling mechanism between PEs argue that BGP offers more drivers and challenges carriers will face in transforming the metro to address data services. scalability and is already proven to work for L3VPNs as defined in RFC 2547. Also, BGP can be used both signaling and PE discovery, whereas LDP isservices used only forhow signaling. BGP what Metrofor Ethernet discusses the adoption of metro Ethernet and that has leduses carriers is called a route reflector to solve the full-mesh PE-to-PE session issue and the fact that, with to the delivery of metro data services. With a changing mix of transport technologies, the book LDP, every time a new and PE is added to trends, the network, a full into mesh needs to virtual be established with all then examines current emerging and delves the role of private networks PEs (in the same VPLS). The route reflector concept allows PEs to operate in a client/server (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic model, where theMPLS PEs peer a single MPLS or multiple route reflectors (for redundancy), and the engineering, and and with Generalized (GMPLS). route reflector relays information between the different PEs. In this case, if a new PE is added to the network, that PE needs to establish only a single peering session with the route reflector. Figure 4-24 shows all PEs peering with a route reflector. A new PE added to the network has to peer only with the route reflector.

Figure 4-24. Signaling Via BGP with Route Reflectors

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and On the what other they hand, can using do forBGP your does organization create the issue of requiring label ranges, because BGP cannot direct label mappings to a specific peer. The use of label ranges is covered in the Learn from the easy-to-read format that enables networking professionals of all levels to upcoming section "L2VPN BGP Model." understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Comparison Between the Frame Relay and MPLS/BGP Approaches Halabi, author of Internet Routing Architectures This section firstwill briefly compares Relay and MPLS L2VPNs and then delves into a Metro networks emerge as theFrame next area of VPNs growth for the networking industry and will discussion about how some IETF drafts proposing BGP are the Frame Relay VPN represent a major shift in how data services are offered to influenced businessesby and residential customers. model. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to As 4-25 shows, a Frame Relay VPN with any-to-any connectivitydata between the demanded different goFigure through fundamental shifts to equip the metro for next-generation services sites requires a full mesh of PVCs between the different CEs. The network uses Frame atthe by enterprise customers and consumers. This is not only a technology shift, but also a Relay shift in the access and Frame Relay/ATM at the edge and core. The physical connection between the operational and business model that will allow the incumbent carriers to transform the metroCE to and Frame Relay network is assigned multiple DLCIs, and each DLCI is used to switch the offerthe enhanced data services. traffic from one CE all the way to another CE. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Figure 4-25. Frame Relay Access, Edge, and Core drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to Such understand networks have drawbacks. First, the whole network is locked into a single technology, the two concepts such as Frame Relay or ATM. Second, adding a new site into the VPN and connecting that site to the rest of from the VPN an operational many PVCs need to be configured Gain the causes experience of industryheadache innovator because and best-selling Cisco Press author, Sam site to site. author of Internet Routing Architectures Halabi, Figure 4-26 shows sameas VPN but with an of MPLS deployment at the coreindustry and with thewill Metro networks willthe emerge the next area growth for the networking and possibility of using Frame Relay, Ethernet, or MPLS at the access. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Figure 4-26. Frame Relay Access and MPLS Edge/Core go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts On the physical connection between the CE and PE, Frame Relay DLCI can still be used to Gain from the experience of industry innovator and best-selling Cisco Press author, Sam indicate the particular these services are now carried through pre-established Halabi, author of service. Internet However, Routing Architectures packet tunnels in the network. The provisioning is now simplified, because rather than Metro networks configuring end-to-end will emerge PVCsas in the thenext network areato ofestablish growth for connectivity the networking between industry the different and will sites, represent the same can a major be accomplished shift in how data by assigning services the are right offered DLCIs to businesses at the CE-to-PE and residential connection; customers. The metro however, the has services always to been different a challenging CEs are environment carried over pre-established for delivering data tunnels services in the because network. it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise L2VPN BGP customers Model and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. The L2VPN BGP model introduces some new terminology for referencing customer sites, customer equipment, and the way blocks of MPLS labels are allocated inservices the network. Metro Ethernet from Cisco Press looks at the deployment of metro data from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the The L2VPN BGP model divides the network into two levels: drivers and challenges carriers will face in transforming the metro to address data services. MetroThe Ethernet discusses the adoption of metro Ethernet services and how that has led carriers provider backbone— Contains all the PEs. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and trends, and delves role ofequipment virtual private The sites— These areemerging the different locations whereinto the the customer (CE)networks resides. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), A site can belong to a single customer and can have one or more CEs. Each CE is traffic engineering, andusing MPLSits and Generalized (GMPLS). referenced own CE ID thatMPLS is unique within the VPLS. In other scenarios, a site can belong to multiple customers, in the case of an MTU, and each customer can have one or more CEs in that site. In this case, a customer connection is represented via a combination site ID and VPLS ID and a physical port on the MTU device.

In the BGP L2VPN scheme, each PE transmits pieces of information such as label blocks and information about the CEs to which it connects to all other PEs. To reach a destination, the PE need only install a route to the site where the destination exits. This allows the service to scale well, because this model tracks the number of VPN sites rather than individual customers. The L2VPN BGP model is generalized to cover the following:
• • Table of of Contents Connectivity a CE to a PE— In this model, the CE is a Frame Relay–capable or MPLSIndex capable device and can allocate a Frame Relay DLCI or an MPLS label after negotiation with Metro the Ethernet PE.
BySam Halabi

Connectivity of a CE to an L2PE and then to a PE— This model reflects an MTU installation where an L2PE is used to connect the multiple customers within a site to a Publisher: Cisco Press common piece of equipment in the basement. The L2PE is similar to the MTU-s that was Pub Date: October 01, 2003 already discussed. The L2PE is a switch that does MAC learning and bridging/switching, and 1-58705-096-X itISBN: encapsulates the Ethernet customer traffic inside an MPLS packet with labels that are Pages: 240 by the PE. In the MTU case, the CE need only have an Ethernet connection to the allocated L2PE and does not need to have any MPLS functionality.

The following section describes an example of an L2VPN with Frame Relay connectivity used on the access and MPLS used on the edge/core. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Example of Frame Relay Access with MPLS Edge/Core
Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can for your organization In this scenario, thedo CEs are connected to the PEs via Frame Relay, and the PEs carry the service over the network using MPLS. This is shown in Figure 4-27. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

Figure 4-27. Frame Relay Access with MPLS Edge/Core
[View full size image]

Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Both CE and PE must agree on the FR DLCI that will be used on the interface connecting them. Each CE that belongs to a VPN is given a CE ID, which is unique in the context of the VPN. In Figure 4-27, a VPN consists of the three CEs: CE1, CE2, and CE3, where CE1 and CE2 are located in site 3 and CE3 is located in site 2. The CE IDs 1, 2, and 3 are supposed to be unique within the same VPN.

Each CE is configured with a list of Frame Relay DLCIs that allows it to connect to the other CEs in the VPN. The size of this list for a particular CE is called the CE's range. In Figure 4-27, for CE3 in site 2 to connect to both CE1 and CE2 in site 3, it would need two DLCIs, one for each remote CE. As such, the CE range determines the number of remote sites a CE can connect to. The larger the range, the more remote CEs a CE can connect to. Each CE also knows which DLCI connects it to every other CE. When a packet comes to a CE from inside the customer network, the CE can use the correct DLCI based on where that packet is going. From then on, the packet • of Contents is "switched"Table from one end to the other. The network behaves as a Frame Relay switch with respect to the • Index CEs.
Metro Ethernet

Each PE is configured with the VPNs in which it participates. For each VPN, the PE has a list of BySam Halabi CEs that are members of that VPN. For each CE, the PE knows the CE ID, the CE range, and which DLCIs to expect from the CE. When a PE is configured with all the needed information for Publisher: Cisco Press a CE, it chooses an MPLS label block, which is a contiguous set of labels. The number of these Pub Date: October 2003 labels is the initial01, CE range, meaning if the CE has a range of ten DLCIs, the PE chooses ten ISBN: 1-58705-096-X MPLS labels. The smallest label in this label block is called the label base, and the number of labelsPages: in the label block is called a label range. The PE then uses BGP Network Layer Reachability 240 Information (NLRI) to advertise the label blocks and the CE ID to which it connects, to all other PEs. Only the PEs that are part of the VPN (through the use of the BGP route target) accept the information. Other PEs discard the information or keep it for future use if they become part of that VPN. The definitive guide to Enterprise and Carrier Metro Ethernet applications. A CE can have one or more label blocks, because when the VPN grows, more CEs participate in the VPN, and the CE label ranges might need to be expanded. If a CE has more than one label block, the notion block offset is used. The block offset identifies the position of services a label block Discover theof latest developments in metro networking, Ethernet, and MPLS and in the set of label blocks of a given CE. what they can do for your organization In reference to Figure 4-27, PEs 1,format 2, and that 3 participate in VPN1. The following isof an example of Learn from the easy-to-read enables networking professionals all levels to the information that needs to be configured on PE1 and the information that PE1 advertises and understand the concepts learns via BGP. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Figure 4-27 shows following: Halabi, authorthe of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will CE3 in site 2 and CE1 and CE2 in site 3 all belong to VPN1, as shown by the dotted line. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has CE3 is given the following set of DLCIs: [10,20,30,40,50,60,70,80,90,100], which been built to handle the stringent reliability and availability needs for voice. Carriers will have to correspond to a CE range of 10 (10 DLCIs). go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not 10 only a technology shift, also 59. a shift in the PE1 is given an MPLS label block that contains labels, from label 50 but to label Label operational and business model that will allow the incumbent carriers to transform the metro to range = 10, label base = 50, block offset = 0. offer enhanced data services. CE1 is given the following set of DLCIs: [100,200,300,400,500,600,700,800,900,1000], Metrowhich Ethernet from Cisco Press looksof at10 the deployment correspond to a CE range (10 DLCIs). of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers andlabel challenges carriers will face10 in transforming the metro to address services. PE3's block for CE1 contains labels, from label 100 to label 109.data Label range = 10, label base = 100, block offset = 0. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a [1,4,6,8,11], changing mixwhich of transport technologies, the book CE2 is given the following set of DLCIs: correspond to a CE range of 5 then examines current and emerging trends, and delves into the role of virtual private networks (5 DLCIs). (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, andblock MPLSfor and Generalized (GMPLS). PE3's label CE2 contains 5MPLS labels, from label 200 to label 204. Label range = 5, label base = 1, block offset = 0. For PE1, the following takes place: 1. PE1 is configured as part of VPN1. BGP route target = VPN1. 2.

1. 2. PE1 is configured to have CE3 be part of VPN1. This can be done by configuring a physical port or a combination physical port and VLAN to be part of VPN1. CE1 is then assigned to that port/VLAN. 3. PE1 learns of CE1 and CE2 and the respective label blocks' offset and label base via BGP NLRI.
• 4. The following Table oflabel Contents information is configured on PE1 for CE3: • Index
Metro Ethernet BySam Halabi

- Label block: 50–59 - Label base = 50

Publisher: Cisco Press Pub Date: October Label01, range 2003 ISBN: 1-58705-096-X Pages: 240

(size of the block) = 10

- Block offset = 0 (there is only one block) Note that PE1's label block is the same size as CE3's range of DLCIs, which is [10, 20, 30, 40, . . . , 100].

- PE1 advertises the ID of CE3 and the label block to all other PEs via BGP NLRI. The definitive guide to Enterprise and Carrier Metro Ethernet applications. The choice of assigning a DLCI to a particular CE is a local matter. Some simple algorithms could be used such that the CE ID of the remote CE becomes an index into the DLCI list of the local CE the latest developments inlist, metro networking, Ethernet, and MPLS andSo, (with Discover index 0 being the first entry in the 1 being the second entry in the list, services and so on). what they can do for your organization for a connection between CE3 and CE1, CE3 could be allocated the second DLCI in the list (DLCI 20) because the remote CE is CE1, and CE1 is allocated the fourth DLCI in its list (DLCI 400) Learn the CE easy-to-read format that enables networking professionals of all levels to because thefrom remote is CE3. understand the concepts The PE in turn can use a simple algorithm to identify which MPLS label is used to reach a remote Gain the experience of industry and best-selling Cisco Press author, CE. In our from example, suppose PE1 receives innovator a BGP NLRI from PE3, indicating that CE1 has Sam a label Halabi, author of Internet Routing Architectures block 100–109. PE1 could use the CE ID of CE3 as an index into CE1's label block. In this case, PE1 could use label 103, which is CE1's label base (100) + CE3's ID (3). PE3 then uses label 51 Metro will emerge as the next area of for the networking industry and (CE3'snetworks label base + 1) to reach CE3. As such, a growth packet coming from CE3 on DLCI 20 is will represent a major shift in how data services are offered to businesses and residential customers. encapsulated with MPLS label 103, and a packet coming from CE1 on DLCI 400 is encapsulated The metro has always been a challenging environment for delivering data services because it has with MPLS label 51. An additional label is used on top of the stack to indicate the PE-to-PE LSP been built to handle the stringent reliability and availability needs for voice. Carriers will have to tunnel between PE1 and PE3. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to DTLS—Decoupling L2PE and PE Functionality offer enhanced data services. The concept Metro Ethernet discussed from Cisco in the Press preceding looks at section the deployment is extended of to metro address data the services Ethernet-to-MPLS from a holistic view. It describes the current scenario—specifically, for MTUmetro, deployments. which isIn based an MTU on TDM scenario, technology, multiple and customers discusses in the the drivers and building arechallenges connected carriers to a basement will face box, in transforming the MTU-s, which the metro is referred to address to as data "L2PE" services. in this section. In this case, the CEs are talking Ethernet to the L2PE, and the L2PE can talk either Metro Ethernet discusses the adoption metro Ethernet services andall how that has led carriers Ethernet or MPLS to the PE. Unlike the of Frame Relay service, in which the connections are P2P, to the delivery of metro data services. With a changing mix of transport technologies, book the Ethernet service allows P2P and MP2MP VPLS service. In a multipoint service, MACthe addresses then examines current and emerging trends, and delves into the role of virtual private networks are used to distinguish how the traffic is directed over the MPLS network. MAC learning in PEs (VPN), virtual privateissues, local area networks virtual private LAN services (VPLS), can cause scalability depending on (VLAN), the L2 service. It is possible to decouple the traffic functions engineering, and MPLS and Generalized MPLS (GMPLS). needed to offer a VPLS service between the L2PE and the PE. These functions consist of the following: MAC learning— Learning MAC addresses from customers in the MTU and from other L2PEs across the metro

STP— Building a loop-free topology on both the LAN side and the metro side Discovery— Discovering other L2PEs connected to the metro It is possible to have the L2PE do the MAC learning and STP functions and to have the PE do the discovery function. As you know, the discovery function can be done via a protocol such as BGP to exchange information between the PEs. The benefit of this decoupling, called Decoupled Transparent LAN Service (DTLS), is to alleviate the PEs from the L2 functionality. Most PEs that • Table of Contents have been deployed in provider networks are IP routers. These routers have been designed for • Index IP core routing and L3 edge functionality and lack most of the functionality of L2 switches. L2 Metro Ethernet switches, on the other hand, come from an enterprise background and lack most of the By Sam Halabi scalability functions offered by L3 IP/MPLS routers. Although new equipment is coming on the market that does both L2 switching and L3 IP routing, Publisher: Cisco Press most of the deployed equipment are routers. DTLS allows the PE to function as IP routers and Pub Date: October 01, 2003 MPLS switches and puts all the L2 functionality in the L2PE. The PE does the VPN/VPLS discovery ISBN: 1-58705-096-X and runs BGP. The L2PE could then be a simpler L2 switch. The L2PE does not have to do any IP Pages: 240 routing or run complex protocols such as BGP. The L2PE needs to be able to do L2 functions, such as MAC learning, STP, and bridging/switching, and be able to label the packets via either VLAN IDs or MPLS labels.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Alleviating PEs from MAC Learning in the DTLS Model One of the main issues for L2VPN services in thenetworking, metro is MAC addressand learning. haveand seen Discover the latest developments in metro Ethernet, MPLS You services in this book that if the service offers a LAN connection between different sites and if the CEs are what they can do for your organization L2 switches (not routers), all MAC addresses that exist in the different connected LANs become part of the VPLS. As an example, assume the following scenario in professionals a hypothetical Learn from the easy-to-read format that enables networking ofmetro: all levels to understand the concepts The contains 60 PEs Gainmetro from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Each PE is connected to ten buildings—that is, ten L2PEs Metro networks will emerge as the next area of growth for the networking industry and will Each L2PE services ten customers represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Each customer has two VPLS been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental to equip the metro for next-generation data services demanded Each VPLS has 100 shifts stations by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow between the incumbent carriers to transform to The following calculations show the difference starting the VPLS service at the the metro L2PE and offer enhanced data services. starting the service at the PE, based on the preceding information. Metro Press looks at the deployment ofsupport metro data services from a holistic If you Ethernet start the from VPLS Cisco service at the L2PE, each L2PE has to the following: view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Ten customers Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers 10 * 2 = 20 VPLS data services. With a changing mix of transport technologies, the book to the delivery of metro then examines current and emerging trends, and delves into the role of virtual private networks 20 * 100 private = 2000local MACarea addresses (VPN), virtual networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Also, because there are 60 * 10 = 600 L2PEs, assuming that each L2PE talks to every other L2PE in a full mesh (BGP or LDP), the number of bidirectional sessions between the L2PEs is 600 * (600 – 1) / 2 = 179,700 sessions. Starting the VPLS service at the PE, the PE has to support the following:

10 * 10 = 100 customers 100 * 2 = 200 VPLS 200 * 100 = 20,000 MAC addresses If there is a full LDP/BGP mesh between the PEs, the number of bidirectional sessions is 60 * (60 – sessions. • 1) / 2 = 1770 Table of Contents
•

From the previous calculations, the following can be easily deduced: Metro Ethernet
BySam Halabi

Index

Doing MAC learning at the L2PE and not at the PE scales much better. Otherwise, the PE has toCisco dealPress with an explosion of MAC addresses. Publisher:
Pub Date: October 01, 2003

Doing a hierarchy in which the full mesh of BGP/LDP sessions starts at the PE prevents a ISBN: 1-58705-096-X session explosion.
Pages: 240

The DTLS model keeps the MAC learning at the L2PE, assigns MPLS labels at the L2PE, and puts the VPLS discovery with BGP or other protocols at the shoulder of the PE. This way, the model can scale much better. The following needs to happen on the L2PE and on the PE: The definitive guide to Enterprise and Carrier Metro Ethernet applications. The L2PE: Discover the latest developments in metro networking, Ethernet, and MPLS services and - Needs as a bridge/switch. It should be able to learn MAC addresses from what they can to dobehave for your organization the building customers and from other L2PEs. Learn from the easy-to-read format that enables networking professionals of all levels to - Should able to send or receive tagged packets. The L2PE should be able to understand thebe concepts perform tag stacking and swapping and handle both VLAN and MPLS tags. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam - Should beInternet able to take an Ethernet frame from a customer-facing port (access Halabi, author of Routing Architectures port), strip the CRC and preamble, and encapsulate the remaining frame using an MPLS packet. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. - An L2PE that receives an MPLS packet should be able to data decide which because VPLS this The metro has always been a challenging environment for delivering services it has packet belongs to and then send it to all customer-facing ports that belong to have the to been built to handle the stringent reliability and availability needs for voice. Carriers will go through VPLS. fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the - Maintains mapping between the learned MAC addresses and the customer's ports operational and business model that will allow the incumbent carriers to transform the metro to and mapping between learned MAC addresses and labels. This mapping constitutes offer enhanced data services. the L2PE's MAC address cache. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic - Maintains a separate MAC address cache per VPLS. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and-challenges carriers willbetween face in transforming the metro to address data services. Maintains a mapping customer-facing ports and the different VPLS. Metro Ethernet discusses the between adoption it of metro services andmodel. how that has - Runs a protocol and the Ethernet PE in a client/server The PE led hascarriers the to the delivery of metro data services. With a changing mix of transport technologies, book intelligence to discover the VPLSs in the network and to inform the L2PE of the right then examines current and emerging trends, and delves into the role of virtual private networks labels (or label blocks, as described earlier). The L2PE uses these labels to reach its (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic destination. engineering, and MPLS and Generalized MPLS (GMPLS). The PE: - Needs to support the L2VPN functionality as described previously in the "L2VPN BGP Model" section. This means that a PE should be able to discover all the VPLSs in

which it participates and distribute information about labels and about other L2PEs in the network. - Runs a PE-to-L2PE protocol that allows the decoupling of functionality between these two devices.

Configuring theof L2PE and PE • Table Contents
• Index

An L2PE needs to be told which VPLS it is a member of. This can be done by statically Metro Ethernet configuring a physical port or port/VLAN as part of a VPLS. In turn, for each (L2PE, VPLS) pair, BySam Halabi the PE needs to be told the site ID of the (L2PE, VPLS). The PE also needs to be told which L2PEs it is connected to, and over which physical link and which VPLSs each L2PE participates in. This Publisher: Cisco Press is illustrated in Figure 4-28.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 4-28. L2PE and PE Configuration

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that willthe allow the incumbent carriers to transform the metro to InFigure 4-28, L2PE1 is configured with following: offer enhanced data services. MetroThe Ethernet Press looks at the deployment of metro data services from a holistic L2PE1from ID isCisco its router ID, 1.1.1.1 view. It describes the current metro, which is based on TDM technology, and discusses the drivers and carriers will face in transforming the metro to address data services. Port 1 challenges (P1) belongs to VPLS1 MetroPort Ethernet discusses the adoption of metro Ethernet services and how that has led carriers 2 (P2) belongs to VPLS2 to the delivery of metro data services. With a changing mix of transport technologies, the book L2PE1 is connected to emerging PE1 then examines current and trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic For the and pair MPLS (L2PE1, VPLS1) the L2PE1 site ID is 1 engineering, and Generalized MPLS (GMPLS). For the pair (L2PE1, VPLS2) the L2PE1 site ID is 1 L2PE1 has a mapping between MAC addresses MAC x-MAC y with VPLS1 L2PE1 has a mapping between MAC addresses MAC z-MAC w with VPLS2

If all information is configured on the PE, the PE can be given information pertinent to the L2PE that it can "push" into the L2PE via a certain client/server protocol. In this case, the PE needs to be configured with the following: L2PE ID (router ID) <connecting interface>
• •
Metro Ethernet BySam Halabi

Table of Contents

<VPLS Index ID> <L2PE site ID> <L2PE port ID, VLAN tag> <L2PE port ID, VLAN tag>

<VPLS ID> <L2PE site ID>
Publisher: Cisco Press

<L2PE ID, Pub Date: October port 01, 2003
ISBN: 1-58705-096-X

VLAN tag> <L2PE port ID, VLAN tag>

For each L2PE and each VPLS that the L2PE participates in, the PE is given the customer-facing Pages: 240 port IDs and corresponding VLAN tags that belong to that VPLS. The PE then transfers all information relevant to that L2PE using the L2PE-PE protocol. The protocol that allows the information exchange between the L2PE and PE can be an extension to LDP or via other protocols. The PE transfers all information relevant to other PEs using the L2VPN BGP mechanism. The definitive guide to Enterprise and Carrier Metro Ethernet applications. The following is a sample configuration for PE1, as shown in Figure 4-28. In this example, PE1 is connected to two different sites, 1 and 2. In site 1, L2PE1 offers service to two customers. Discover latest developments in metro networking, Ethernet, services and Customer 1 onthe port 1 has VPLS1, which emulates a LAN between VLANand 100MPLS across different sites what they can do for your organization (sites 1, 2, and 3). Customer 2 has VPLS2, which emulates a LAN for all VLANs. Learn from the easy-to-read format that enables professionals of all levels to PE1 is connected to L2PE1 and L2PE2. The following is networking the configuration for L2PE1 in PE1: understand the concepts L2PE1 Gain from has the router experience ID 1.1.1.1 of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Connecting interface: P1 Metro networks will emerge as the next area of growth for the networking industry and will <VPLS 1, siteshift ID 1> represent a major in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to <L2PE1 port 1, VLAN 100> go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the <VPLS 2, site ID 1> operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. - <L2PE1 port 2, all> Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view.For It describes VPLS1: the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services how that has led carriers - WAN label block 50–59, label range = 10, label base and = 50, block offset =0 to the delivery of metro data services. With a changing mix of transport technologies, the book then examines - L2PE current labeland block emerging 30–39, label trends, range and = delves 10, label into base the role = 30, of virtual block offset private =0 networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic For VPLS2: engineering, and MPLS and Generalized MPLS (GMPLS). - WAN label block is x - L2PE label block is y

The following is the configuration for L2PE2 in PE1: L2PE2 has router ID 2.2.2.2 Connecting interface: P2 <VPLS 1, site ID 2>
• •
BySam Halabi

Table of Contents Index

- <L2PE2 Metro Ethernet For VPLS1:

port 1, VLAN 100>

Publisher: Cisco Press

WAN 01, label is Pub Date: October 2003
ISBN: 1-58705-096-X Pages: 240

etc.

- L2PE label block is etc.

Note that the PE1 configuration includes the indication of label blocks and label ranges. This is the same concept discussed earlier for the Frame Relay scenario; however, two sets of label blocks need to be configured for each PE. One set, called the WAN label block, is used to direct traffic received from L2PEs served by other PEs to the correct L2PE served by this PE. The other set label blocks is to the L2PE label block that Metro tells the L2PEs applications. which label to use when sending Theof definitive guide Enterprise and Carrier Ethernet traffic to another L2PE. This creates in the network a hierarchy where the L2PEs exchange information with the connected PEs and the PEs exchange information with each other. Discover the latest developments in metro networking, Ethernet, and MPLS services and The site what IDthey of an can L2PE do could for your be organization used as an offset from a label base to create a label. The next two sections explain how this is applied for WAN labels and the L2PE labels. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

WANGain Labels from the experience of industry innovator and best-selling Cisco Press author, Sam
Halabi, author of Internet Routing Architectures For VPLS1, PE3, which is connected to L2PE3 in site 3, sends a BGP advertisement to PE1. This advertisement contains PE3's WAN label area baseof ofgrowth 100, a for block offset of 0 (because only Metro networks will emerge as the next the networking industry andone willlabel block is used), andshift the label range 10. represent a major in how dataof services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has For VPLS1, PE1, which isstringent connected to L2PE1 in site 1, sends a BGP advertisement to will PE3. Thisto been built to handle the reliability and availability needs for voice. Carriers have advertisement contains PE1's WAN label base of 50, a block offset of 0, and a label range of 10. go through fundamental shifts to equip the metro for next-generation data services demanded PE1 also sends advertisements for all the <L2PE, VPLS> pairs it connects to, such as <L2PE1, by enterprise customers and consumers. This is not only a technology shift, but also a shift in the VPLS2> andand L2PE2 and its respective VPLS. operational business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. PE1 uses label 101 when sending packets to L2PE3. This is calculated by taking PE3's label base (100) and adding PE1's site ID (1). PE3 label 53 when packets to L2PE1. is Metro Ethernet from Cisco Press looks atuses the deployment of sending metro data services from aThis holistic calculated by taking PE1's label base (50) and adding PE3's site ID (3). view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro L2PE Ethernet Labels discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then current a and trends, and delves into the role ofbe virtual networks Each examines PE also allocates setemerging of label blocks, called L2PE labels, that will usedprivate by the L2PEs. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic For VPLS1, PE1 sends to L2PE1 a label base of 30, a label range of 10, and a block offset of 0. engineering, and MPLS and Generalized MPLS (GMPLS). For VPLS1, PE3 sends to L2PE3 a label base of 20 and a range of 10. L2PE1 uses label 33 when sending packets to PE1. This is calculated by taking PE1's label base (30) and adding L2PE3's site ID (3). L2PE3 uses label 21 when sending packets to PE3. This is calculated by adding PE3's label base (20) to L2PE1's site ID (1).

Following a packet in VPLS1 from L2PE1, L2PE1 takes the Ethernet frame coming from port 1, VLAN 100, and encapsulates it in an MPLS frame with label 33. PE1 receives the packet with label 33 and swaps this label with label 101, which is sent to L2PE3. PE1 encapsulates another PE-to-PE label, which directs the packet from PE1 to PE3. When the packet reaches PE3, PE3 swaps the label 103 for a label 21 and directs the packet to L2PE3. Based on this label, L2PE3 directs the packet to VPLS1. Flooding, learning, and spanning-tree behavior at the L2PE are similar to what was previously • Table of Contents described with the L2VPN and the LDP PW model. When a packet with an unknown destination • Index reaches the L2PE, the L2PE identifies to which VPLS this packet belongs. It then replicates the Metro Ethernet packet over all ports in the VPLS. If the packet is received on a customer-facing port, the L2PE By Sam Halabi sends a copy out every other physical port or VLAN that participates in the VPLS, as well as to every other L2PE participating in the VPLS. If the packet is received from a PE, the packet is sent to only customer-facing ports in the MPLS, assuming that a full mesh of PEs already exists. Publisher: Cisco Press If an L2PE wants to flood a VPLS packet to all other L2PEs in the VPLS, the L2PE sends a copy of ISBN: 1-58705-096-X the packet with each label in the L2PE label ranges for that VPLS, except for the label that Pages: 240 corresponds to the L2PE itself. The drawback of doing the flooding at the L2PE is that the L2PE is connected to many other L2PEs in other sites and has to do quite a lot of replications. You have to weigh this against the benefits of removing the MAC learning from the PEs and keeping it in the L2PEs. The definitive guide to Enterprise and Carrier Metro Ethernet applications. As mentioned, the protocol used for the PE-to-L2PE information exchange can be an extension of LDP. Also, there is no technical restriction on whether the tags used between the L2PE and the PE are Discover MPLS labels. the latest Using developments VLAN tags with in metro Q-in-Q networking, is also a possibility. Ethernet,The andchoice MPLS of services one approach and or the what other they is implementation-specific can do for your organization and depends on the L2PE and PE equipment capability. The upper VLAN tag sent between the L2PE and the PE is indicative of the VPLS. The PE needs to Learn from the the easy-to-read that enables networking of all levels to match that tag with right WANformat label to transport the packet to professionals the remote L2PEs. It is also understand the concepts possible to use LDP as a universal protocol to allow the exchange of Q-in-Q tags between the PE and L2PE in the same way that MPLS labels are exchanged. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
Pub Date: October 01, 2003

Conclusion
You have seen in this chapter how IP/MPLS can be used to scale L2 Ethernet service deployments. By keeping L2 Ethernet networks confined to the access/edge and IP/MPLS at the edge/core, service providers can leverage the simplicity of deploying Ethernet LANs with the • Table of Contents scalability offered by IP and MPLS. L2 Ethernet services can be offered as P2P or MP2MP • Index services. P2P can be achieved via mechanisms such as L2TPv3 or EoMPLS draft-martini. MP2MP Metro Ethernet can be achieved via VPLS.
BySam Halabi

You have seen that the flexibility VPLS offers with any-to-any connectivity is also coupled with the drawbacks of delivering Ethernet LANs in dealing with L2 loops and broadcast storms. Also Publisher: Cisco Press with VPLS come the challenges of dealing with MAC address explosion, because PEs have to keep Pub Date: October 01, 2003 track of all MAC addresses advertised within the VPLS(s) the PEs belong to. Some alternatives, ISBN: 1-58705-096-X such as DTLS, are proposed for dealing with MAC explosion; however, different network designs Pages: 240 and different L2PE-to-PE protocols would have to be defined and standardized. Part II of this book, starting with Chapters 5 and 6, builds on the fact that scalable L2VPN networks are built with hybrid Ethernet and IP/MPLS networks. It also focuses on scaling the MPLS portion of the network with mechanisms such as traffic engineering via RSVP-TE and traffic protection via guide MPLS to fast reroute. Chapters 7 and 8 move into applications. the more advanced topic of The definitive Enterprise and Carrier Metro Ethernet Generalized MPLS (GMPLS). Metro networks are built with legacy TDM technology, so it is important to understand how the proliferation of MPLS in the metro will affect network provisioning on both packet and TDM networks—hence the need for a generalized control and plane Discover the latest developments in metro networking, Ethernet, and MPLS services like GMPLS. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Part II: MPLS: Controlling Traffic over Your Optical Metro
• • Table of Contents Chapter 5 MPLS Traffic Engineering Index

Chapter 6 RSVP Metro Ethernet
BySam Chapter Halabi 7

for Traffic Engineering and Fast Reroute

MPLS Controlling Optical Switches

Chapter 8 GMPLS Architecture
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 5. MPLS Traffic Engineering
This chapter covers the following topics:
• •

Advantages of Traffic Engineering
Index

Table of Contents

Metro Pre-MPLS Ethernet BySam Halabi

Traffic Engineering Techniques

MPLS and Traffic Engineering You have seen in the previous chapters how metro Ethernet Layer 2 (L2) services can be Pub Date: October 01, 2003 deployed over an MPLS network. You also learned about the concept of pseudowires and label ISBN: 1-58705-096-X switched path (LSP) tunnels. The LSP tunnels are simply a means to tunnel the pseudowires Pages: 240 from one end of the MPLS cloud to the other with the opportunity of aggregating multiple pseudowires within a single LSP tunnel. The LSP tunnels themselves can be constructed manually, or via MPLS signaling using the Label Distribution Protocol (LDP) or RSVP traffic engineering (TE). TE is an important MPLS function that gives the network operator more control over how traffic traverses the network. This chapter details the concept of TE and its use. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
Publisher: Cisco Press

Advantages of Traffic Engineering
One of the main applications of MPLS is TE. A major goal of Internet TE is to facilitate efficient and reliable network operations while simultaneously optimizing network resource utilization and traffic performance. TE has become an indispensable function in many large provider networks • Table of Contents because of the high cost of network assets and the commercial and competitive nature of the • Index Internet.
Metro Ethernet

The purpose BySam Halabi of TE is to optimize the performance of operational networks. TE forces packets to take predetermined paths to meet network policies. In general, TE provides more efficient use of available network resources; provides control of how traffic is rerouted in the case of failure; Publisher: Cisco Press enhances performance characteristics of the network relative to packet loss, delay, and so on; Date: October 01, 2003 andPub enables value-added services, such as guaranteeing QoS and enforcing SLAs.
ISBN: 1-58705-096-X

With metro Pages: 240 Ethernet services, you have seen that setting bandwidth parameters on the UNI connection between the customer edge (CE) and the provider edge (PE) devices is part of the service sold to the customer. An Ethernet service with a committed information rate (CIR) of 1 Mbps should guarantee the customer that much bandwidth. It is the service provider's duty to make sure that the bandwidth promised to the customer can be allocated on the network and that the trafficguide adheres to the packet and Metro delay Ethernet parameters that are promised. TE gives the The definitive to Enterprise andloss Carrier applications. service provider more control over how traffic from multiple customers is sent over the network, enabling the service provider to make the most use of the resources available and to optimize performance. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization In reference to RFC 2702, Requirements for Traffic Engineering over MPLS, the key performance objectives TE the can easy-to-read be classified as either of the following: Learnfor from format that enables networking professionals of all levels to understand the concepts Traffic-oriented Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Resource-oriented Metro networks will emerge as the next area of growth for the networking industry and will Traffic-oriented performance objectives deal are with traffic characteristics such as minimizing loss represent a major shift in how data services offered to businesses and residential customers. and delay to enhance traffic quality. In reference to the performance parameters defined in The metro has always been a challenging environment for delivering data services because it has Chapter 3,to "Metro Ethernet Services," trafficand characteristics availability, delay, jitter, and been built handle the stringent reliability availability include needs for voice. Carriers will have to packet loss. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Resource-oriented performance objectives are mainly concerned with the optimization of operational and business model that will allow the incumbent carriers to transform the metro to resource utilization. The top priority of these objectives is to manage bandwidth resources offer enhanced data services. through congestion control. Network congestion typically manifests under two scenarios: Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view.When It describes the current metro, which is based on TDM to technology, and discusses network resources are insufficient or inadequate accommodate the trafficthe load. An drivers and challenges carriers will face in transforming the metro to address dataedge services. example is a spoke between a multitenant unit (MTU) device and a provider router at the central office (CO) that has less bandwidth than required to service all the customers of Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers the building according to an agreed-upon SLA with the service provider. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current andare emerging trends, and delves into the role of virtual private networks When traffic streams inefficiently mapped onto available resources, causing subsets of (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic is network resources to become overutilized while others remain underutilized. An example engineering, and MPLS and Generalized MPLS the existence of multiple parallel links on (GMPLS). the backbone where some of these links are oversubscribed and are dropping traffic while others are sitting idle. This is because of how Interior Gateway Protocols (IGPs) calculate the shortest path, as explained in the next section. Expanding capacity, or overprovisioning, alleviates the first type of congestion. Adding more or

bigger network pipes is a quick and easy fix, but it comes at additional cost. Other classic congestion-control techniques, such as rate limiting, queue management, and others, can also be used to deal with insufficient network resources. These techniques are important to prevent a set of users or traffic types from consuming the whole bandwidth and starving other users on the network. This chapter mainly addresses the second type of congestion problems—those resulting from inefficient resource allocation. You can usually address these congestion problems through TE. In • Table of Contents general, you can reduce congestion resulting from inefficient resource allocation by adopting • Index load-balancing policies. The objective of such strategies is to minimize maximum congestion, or Metro Ethernet alternatively to minimize maximum resource utilization, through efficient resource allocation. By Sam Halabi When congestion is minimized through efficient resource allocation, packet loss decreases, transit delay decreases, and aggregate throughput increases. This significantly enhances the end users' perception of network service quality. Publisher: Cisco Press As you have noticed, this chapter so far hasn't mentioned MPLS, because TE by itself is universal ISBN: 1-58705-096-X and a well-understood problem. The use of MPLS for TE is one of the methods for dealing with Pages: 240 resource optimization, and the industry has begun adopting MPLS techniques only after going through many alternatives to solve the TE problem. The next section discusses some of the preMPLS TE techniques.
Pub Date: October 01, 2003

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Pre-MPLS Traffic Engineering Techniques
Pre-MPLS TE techniques involved multiple mechanisms: Altering Table IGP of routing Contents metrics
Index

• •

Metro Equal-cost Ethernet BySam Halabi

multipath

Policy-based routing virtual circuit overlays

Publisher: OfflineCisco design Press of

Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: IGP 240 Altering Routing Metrics

IGPs have many limitations when used to achieve traffic engineering. IGPs rely on metrics that do not reflect actual network resources and constraints. IGPs based on Shortest Path First (SPF) algorithms contribute significantly to congestion problems in IP networks. SPF algorithms generally optimize based on a simple metric. These protocols are topology-driven, so The definitive guide to Enterprise and additive Carrier Metro Ethernet applications. real-time bandwidth availability and traffic characteristics are not factors considered in routing decisions. As such, congestion occurs when the shortest paths of multiple streams converge over Discover the latest developments inother metro networking, Ethernet, and MPLS and one link that becomes overutilized while existing links are underutilized, asservices shown in what they can do for your organization Figure 5-1. Learn from the easy-to-read format that enables networking professionals of all levels to 5-1. IGP Shortest Path First Congestion understand Figure the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). InFigure 5-1, based on the indicated link metric, an OSPF routing algorithm allows traffic coming from routers A and B, destined for router H, to use path C-G-I-H. Traffic from routers E and G, destined for H, uses path G-I-H. As you can see, multiple streams of traffic have converged on the same links or routers, causing congestion on link G-I, for example, while other links in the network remain underutilized.

Altering IGP metrics could cause traffic to shift between links. Changing the metric of link F-H from 15 to 10 or 5 could cause the traffic to start taking links C-D-F-H or C-G-F-H. Link manipulation for the purposes of TE works for quick-fix solutions but is mainly a trial-and-error process and does not scale as an operational model. Adjusting the link metrics might fix one problem but create other problems in the network.

• Table of Contents Equal-Cost Multipath • Index
Metro Ethernet Equal-cost multipath

is a mechanism that allows routers to distribute traffic between equal-cost links By Samto Halabi efficiently use the network resources and avoid the problem of link oversubscription and undersubscription. If, for example, a router calculates the shortest path based on link metrics andPublisher: determines multiple equal paths exist to the same destination, the router can use loadCisco Press balancing techniques to spread the traffic flows over the equal-cost links. Referring to Figure 5Pub Date: October 01, 2003 1, if the metric of link F-H is changed to 10 instead of 15, the paths C-D-F-H and C-G-I-H would ISBN: 1-58705-096-X have the same metric, 30 (10 + 10 + 10). Traffic from routers A and B, destined for H, could be Pages: 240 load balanced across the two equal-cost paths.

Policy-Based Routing
The definitive guide to Enterprise and Carrier Metro Ethernet applications. Policy-based routing is another mechanism that can be used for TE. It allows routers to dictate the traffic trajectory. That is, they pick the router output interface on which to route traffic based on a policy—for example, based on thein source IP address rather than the destination IP address. Discover the latest developments metro networking, Ethernet, and MPLS services and With this type of TE,do you can dictate that traffic coming from a certain customer or provider goes what they can for your organization one way, while traffic from other customers or providers goes the other way, irrespective of what Learn from the easy-to-read format that enables networking professionals of all levels to its actual destination is. understand the concepts Policy-based mechanisms can be used to allow more granularity in identifying the source traffic. Gain from the experience industry innovator and best-selling Press Sam For example, the traffic can be of identified based on source IP address,Cisco router port author, numbers, QoS, Halabi, author of Internet Routing Architectures application type, and so on. Although this type of TE is useful, it has its drawbacks. First, it acts against the nature of routing, which is primarily destination-based. Second, it becomes yet Metro networks emerge as the next area growth for to the networking industry and will another form of will intelligent static routing with of vulnerability traffic loops and to the lack of represent a major shift in how data services are offered to businesses and residential customers. dynamic rerouting in case of failure of network elements. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Offline Design of Virtual Circuit Overlays by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to A popular approach circumvent the inadequacies of current IGPs is to use an overlay model, offer enhanced data to services. such as IP over ATM or IP over Frame Relay. The overlay model extends the design space by Metro Ethernet enabling arbitrary from virtual Cisco topologies Press looks toat be the provisioned deployment on of top metro of the data network's services physical from a topology. holistic view. The virtual It describes topology the iscurrent constructed metro, from which virtual is based circuits on (VCs) TDM technology, that appearand as physical discusses links the to the drivers IGP routing and challenges protocols. Overlay carriers techniques will face in can transforming range from the simple metro permanent to addressvirtual data services. circuit (PVC) provisioning between routed edge networks to more fancy mechanisms that include constraintMetro discusses the adoption of metro Ethernet services how that hasshaping led carriers based Ethernet routing at the VC level with support of configurable explicit and VC paths, traffic and to the delivery of metro data services. With a changing mix of transport technologies, the book policing, survivability of VCs, and so on. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), 5-2 Figure virtual shows private edge local routers area that networks are connected (VLAN), to virtual eachprivate other via LAN anservices overlay (VPLS), model on traffic top of engineering, an ATM network. and MPLS For the and IGPs, Generalized the VCs appear MPLS (GMPLS). as direct physical links between the routers. Traffic can be engineered between the routed edges and is agnostic to the L2 switched network in the middle of the cloud. This type of TE has several benefits: It enables you to achieve full traffic control, measure link statistics, divert traffic based on link utilization, apply loadbalancing techniques, and so on. It also has several obvious drawbacks: It creates multiple independent control planes—IP and ATM—that act independently of one another, a full mesh

between the routers, an IGP neighbor explosion (each router has all other routers as neighbors and has to exchange routing updates with them), and finally a network management challenge constituting multiple control layers.

Figure 5-2. IGP TE Via Virtual Circuit Overlays
• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

MPLS and Traffic Engineering
MPLS is strategically significant for TE because it can potentially provide most of the functionality available from the overlay model (described in the preceding section), with much better integration with IP. MPLS for TE is attractive because it enables you to do the following:
• •
BySam Halabi

Table of Contents Index

Metro Manually Ethernet

or dynamically build explicit LSPs

Efficiently manage LSPs and map them to LSPs

Publisher: Press DefineCisco traffic trunks Pub Date: October 01, 2003

Associate a set of attributes with traffic trunks to change their characteristics ISBN: 1-58705-096-X Associate a set of attributes with resources that constrain the placement of LSPs and traffic trunks mapped to those LSPs Aggregate and deaggregate traffic (whereas IP routing only allows aggregation) Easily incorporate a constraint-based routing framework with MPLS The definitive guide to Enterprise and Carrier Metro Ethernet applications. Deliver good traffic implementation with less overhead than pre-MPLS techniques Discover the latest developments in metro networking, Ethernet, and MPLS services and Define backup paths failover what they can do for with your fast organization Before delving into more details about TE, it helps to explain the terminology of of trunks versus Learn from the easy-to-read format that enables networking professionals all levels to LSPs,understand because the two are often confused with one another. the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures
Pages: 240

Traffic Trunks Versus LSPs

Metro networks will emerge as the next area of growth for the networking industry and will Traffic trunks are not LSPs. The definition of are traffic trunks indicated and in RFC 2430 follows: "A represent a major shift in how data services offered toas businesses residential customers. traffic trunk is an aggregation of traffic flows of the same which data are placed inside an LSP." The metro has always been a challenging environment forclass delivering services because it has Examples classes can be similar to Diffserv. Traffic trunks routable objects, been built of to flow handle the stringent reliability and availability needsare for also voice. Carriers will have to similar to VCs for ATM. Ashifts traffic trunk can be mapped to a set of LSPs and be moved from go through fundamental to equip the metro for next-generation datacan services demanded one LSP to another. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to An LSP, on the other hand, is a specification of the path through which the traffic traverses. The offer enhanced data services. LSP is constructed through label swapping between ingress to egress to switch the traffic to its destination. Trunks traverse LSPs and can bedeployment routed fromof one LSP data to another. This is illustrated Metro Ethernet from Cisco Press looks at the metro services from a holistic in Figure 5-3. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 5-3. Trunks and LSPs

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 5-3 shows two LSPs between routers C and H, LSP C-D-F-H and LSP C-G-I-H. Another LSP exists between routers F and H, LSP F-G-I-H. A set of traffic flows belonging to the same class, coming from router A and destined for destinations beyond router H, could be mapped to either LSP C-D-F-H or LSP C-G-I-H. This aggregated traffic flow is the traffic trunk. The same traffic trunk can be routed over LSP F-G-I-H some Ethernet trunk attributes, such as resiliency or The definitive guide to Enterprise and CarrierifMetro applications. bandwidth, are being enforced. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

Capabilities of Traffic Engineering over MPLS

Learn from the easy-to-read format that enables networking professionals of all levels to The functional capabilities required to support TE over MPLS in large networks involve the understand the concepts following: Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures A set of attributes that affect the behavior and characteristics of traffic trunks Metro networks will emerge as the next area of growth for the networking industry and will A seta of attributes that are associated with that constrain the placement of represent major shift in how data services are resources offered to and businesses and residential customers. traffichas trunks over LSPs The metro always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to A constraint-based that isfor used to select paths subject to constraints go through fundamental routing shifts toframework equip the metro next-generation data services demanded imposed by traffic trunk attributes and available resources by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to The attributes associated with traffic trunks and resources, as well as parameters associated with offer enhanced data services. routing, represent a set of variables that can be used to engineer the network. These attributes can beEthernet set either manually or through means. of The next data section discusses trunk Metro from Cisco Press looks automated at the deployment metro services fromtraffic a holistic operation and attributes. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet the adoption of metro Ethernet services and how that has led carriers Traffic Trunk discusses Operation and Attributes to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the of virtual private networks Traffic trunks are by definition unidirectional, but it is possible to role instantiate two trunks in (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic opposite directions with the same endpoints. The set of traffic trunks, one called forward trunk engineering, MPLS and Generalized MPLS (GMPLS). and the otherand called backward trunk, form a logical bidirectional traffic trunk. The bidirectional traffic trunks can be topologically symmetrical or asymmetrical. A bidirectional traffic trunk is symmetrical if opposite trunks take the same physical path, and it is asymmetrical if opposite trunks take different physical paths. The basic operations that you can perform on a trunk include establishing a trunk; activating,

deactivating, and destroying a trunk; modifying a trunk's attributes; and causing a trunk to reroute from its original path via manual or dynamic configuration. You can also police the traffic to comply with a certain SLA and shape and smooth the traffic before it enters the network. As described in RFC 2702, the following are the basic attributes of traffic trunks that are particularly significant for TE:
• •
BySam Halabi

Table of Contents Traffic parameter attributes Index

Metro Generic Ethernet

path selection and maintenance attributes

Priority attribute

Publisher: Cisco Press Preemption attribute Pub Date: October 01, 2003

Resilience attribute ISBN: 1-58705-096-X Policing attribute Resource attributes
Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Traffic Parameter Attributes Traffic parameter indicate the requirements of a traffic are useful Discover the attributes latest developments inresource metro networking, Ethernet, and trunk MPLS that services and for resource allocation congestion avoidance. Such attributes include peak rates, average what they can do and for your organization rates, permissible burst size, and so on. Chapter 3 describes the applicable parameters, such as committed Learn information from the easy-to-read rate (CIR),format peak information that enables rate networking (PIR), and professionals so on. of all levels to understand the concepts GainPath from Selection the experience industry innovator and best-selling Cisco Press author, Sam Generic andof Maintenance Attributes Halabi, author of Internet Routing Architectures Generic path selection and maintenance attributes define how are selected, such via Metro networks will emerge as the next area of growth for the paths networking industry and as will underlying network protocols, via manual means, or via signaling. If no restrictions exist on how represent a major shift in how data services are offered to businesses and residential customers. a traffic trunk is established, IGPs can be used to select a path. If restrictions exist, constraintThe metro has always been a challenging environment for delivering data services because it has based routing signaling, such as RSVP-TE, should be used. needs for voice. Carriers will have to been built to handle the stringent reliability and availability go through fundamental shifts to equip the metro for next-generation data services demanded Chapter 4, "Hybrid L2 and L3consumers. IP/MPLS Networks," describes how a metro provider carries L2 by enterprise customers and This is not only a technology shift, but also a shift in the services over an MPLS cloud via the use of pseudowires (VC-LSPs) carried in LSP tunnels. If the operational and business model that will allow the incumbent carriers to transform the metro to LSP tunnels are not traffic-engineered, the traffic on the MPLS cloud follows the path dictated by offer enhanced data services. the IGP. If multiple IGP paths collide, traffic congestion could occur. Setting resource requirements coupled with Press TE alleviates Metro Ethernet from Cisco looks atthis the problem. deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services.

Priority Attribute
Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data the services. With a changing of trunks. transport technologies, the book The priority attribute defines relative importance of mix traffic Priorities determine which then examines current and emerging trends, and delves into the role of virtual private networks paths should be used versus other paths at connection establishment and under fault scenarios. (VPN), virtual private local area networks (VLAN), virtual LAN services over (VPLS), traffic A metro operator could deliver Internet service as well as private IP storage backhaul different engineering, and MPLS and Generalized MPLS (GMPLS). pseudowires. The IP storage traffic could be carried over a separate LSP tunnel and given a high priority to be rerouted first in case of failure.

Preemption Attribute

The preemption attribute determines whether a traffic trunk can preempt another traffic trunk from a given path. Preemption can be used to ensure that high-priority traffic can always be routed in favor of lower-priority traffic that can be preempted. Service providers can use this attribute to offer varying levels of service. A service that has preemption could be priced at a higher rate than a regular service.

• Table of Contents Resilience Attribute • Index
Metro Ethernet The resilience

attribute determines the behavior of a traffic trunk when fault conditions occur along the path through which the traffic trunk traverses. The resiliency attribute indicates By Sam Halabi whether to reroute or leave the traffic trunk as is under a failure condition. More extended resilience attributes could specify detailed actions to be taken under failure, such as the use of Publisher: Cisco Press alternate paths, and specify the rules that govern the selection of these paths.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X

Policing Attribute
The policing attribute determines the actions that should be taken by the underlying protocols when a traffic trunk exceeds its contract as specified in the traffic parameters. Policing is usually done on the input of the network, and it indicates whether traffic that does not conform to a The definitive guide to Enterprise and Carrier Metro Ethernet applications. certain SLA should be passed, rate limited, dropped, or marked for further action. Discover the latest developments in metro networking, Ethernet, and MPLS services and

Pages: 240

Resource Attributes what they can do for your organization
Learn from theconstrain easy-to-read format that networking professionals of all levels to Resource attributes the placement ofenables traffic trunks. An example of resource attributes understand the concepts is the maximum allocation multiplier. This attribute applies to bandwidth that can be oversubscribed or undersubscribed. This attribute is comparable to the subscription and booking Gain from the experience of industry innovator and best-selling Cisco Press author, Sam factors in ATM and Frame Relay. A resource is overallocated or overbooked if the sum of traffic Halabi, author of Internet Routing Architectures from all traffic trunks using that resource exceeds the resource capacity. Overbooking is a typical mechanism used by service providers to take advantage of the traffic's statistical multiplexing Metro networks will emerge as the next area of growth for the networking industry and will and the fact that peak demand periods for different traffic trunks do not coincide in time. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Another example of resource attributes is the resource class attribute, which attempts to give a been built to handle the stringent reliability and availability needs for voice. Carriers will have to "class" to a set of resources. Resource class attributes can be viewed as "colors" assigned to go through fundamental shifts to equip the metro for next-generation data services demanded resources such that resources with the same "color" conceptually belong to the same class. The by enterprise customers and consumers. This is not only a technology shift, but also a shift in the resource class attribute can be used to implement many policies with regard to both traffic- and operational and business model that will allow the incumbent carriers to transform the metro to resource-oriented performance optimization. Resource class attributes can be used, for example, offer enhanced data services. to implement generalized inclusion and exclusion to restrict the placement of traffic trunks to a specific subset of resources. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services.

Constraint-Based Routing

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix ofof transport technologies, the book Constraint-based routing assists in performance optimization operational networks by finding then examines current and emerging trends, and delves into the role of virtual private networks a traffic path that meets certain constraints. Constraint-based routing is a demand-driven, (VPN), virtual private local mechanism area networks (VLAN), virtual private LANIGP services (VPLS), traffic reservation-aware routing that coexists with hop-by-hop routing. engineering, and MPLS and Generalized MPLS (GMPLS). Constraints are none other than the attributes that were previously discussed: Trunk attributes such as path selection attributes, policing, preemption, and so on, coupled with resource attributes and some link-state parameter, would affect the characteristics and behavior of the traffic trunk.

A constraint-based routing framework can greatly reduce the level of manual configuration and intervention required to set TE policies. In practice, an operator specifies the endpoints of a traffic trunk and assigns a set of attributes to the trunk. The constraint-based routing framework is then expected to find a feasible path to satisfy the expectations. If necessary, the operator or a TE support system can then use administratively configured explicit routes to perform finegrained optimization. Figures 5-4a and 5-4b show two different types of routing applied to the same scenario. In • Table of Contents Figure 5-4a, simple IGP routing is applied, and the shortest path is calculated based on the IGP • Index metrics. A traffic trunk coming from router A is mapped to path (LSP) C-E-G-I-H. In Figure 5-4b, Metro Ethernet constraints are imposed on the routing construct. The constraint is not to use any path that has By Sam Halabi available bandwidth less than 250 Mbps. As such, the two links E-G and G-I have been removed, or pruned, from the selection algorithm, and the traffic trunk coming from router A has been mapped to path C-D-G-F-H. Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 5-4a. Aggregating Trunks into Tunnels

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Figure 5-4b. Constraint-Based Routing The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
This chapter has discussed the different parameters used for TE. Some of the concepts, such as traffic parameter attributes and policing attributes, were discussed in the context of metro deployments in Chapter 3.
• Table of Contents • Index The next steps for TE entail a mechanism for exchanging the traffic attributes and parameters in Metro Ethernet for each router to build a TE database. This database gives the routers visibility to the network all theHalabi network resources and attributes that can be used as input into a Constrained Shortest BySam Path First (CSPF) algorithm. CSPF determines the path in the network based on different constraints and attributes. Finally, a signaling protocol such as RSVP-TE is used to signal the LSP Publisher: Cisco Press in the network based on the path determined by the CSPF. The next chapters explain the Pub Date: October 01, 2003 concepts behind RSVP-TE to familiarize you with how Label Switched Path are signaled across a 1-58705-096-X packetISBN: network. The book extends this concept further in Chapters 7 and 8 to discuss how MPLS Pages: 240 signaling and routing can be extended as well to cover nonpacket networks, such as the case of an optical metro.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 6. RSVP for Traffic Engineering and Fast Reroute
• of Contents This chapter Table covers the following topics: •
Metro Ethernet BySam Halabi

Index

Understanding RSVP-TE Understanding MPLS Fast Reroute

Publisher: Cisco Press

Traffic engineering allows Pub Date: October 01, 2003 the service provider to manipulate the traffic trajectory to map traffic demand to network resources. You have seen in Chapter 5, "MPLS Traffic Engineering," that ISBN: 1-58705-096-X trafficPages: engineering can be achieved by manipulating Interior Gateway Protocol (IGP) metrics or, 240 better yet, by using a signaling protocol such as RSVP-TE. RSVP-TE offers the ability to move trunks away from the path selected by the ISP's IGP and onto a different path. This allows a network operator to route traffic around known points of congestion in the network, thereby making more efficient use of the available bandwidth. It also allows trunks to be routed across engineered paths that provide guaranteed service levels, enabling the sale of classes of service. The definitive guide to Enterprise and Carrier Metro Ethernet applications. In metro networks, traffic engineering goes hand in hand with traffic path restoration upon failures. The behavior of a network upon failure depends on what layer the restoration methods Discover latest developments in metro networking, Ethernet, and MPLS services and are applied to.the SONET/SDH networks, for example, can achieve restoration at Layer 1, meaning what they can do for your organization that if part of a SONET/SDH ring fails, there is always a backup TDM circuit provisioned on another fiber (unidirectional path switched ring, UPSR) or another pair of fibers (bidirectional Learn from the easy-to-read format that enables networking professionals of all levels to line switched ring, BLSR). With Resilient Packet Ring (RPR), the ring is always fully utilized and a understand the concepts failure will cause the ring to wrap, allowing the rest of the ring to remain functional. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Restoration can also be done at Layer 2. Spanning Tree Protocol (STP) and Rapid Spanning Tree Halabi, author of Internet Routing Architectures Protocol (RSTP) (802.1w) are typical methods that allow the network to converge after failure. Layer methods can also beas used. Routing protocols such Open Shortest Path First Metro 3 networks will emerge the next area of growth for as the networking industry and(OSPF) will and Intermediate System-to-Intermediate System (IS-IS) are capable of computing represent a major shift in how data services are offered to businesses and residentialmultiple customers. paths to the same destination. If the mainenvironment path fails, the protocols converge to an alternate The metro has always been a challenging for delivering data services because it has path. Mechanisms like equal-cost multipaths can also be used to allow faster convergence by to been built to handle the stringent reliability and availability needs for voice. Carriers will have having parallel active paths to the same destination. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the In the use of traffic engineering and traffic restoration methods, operators look for the following: operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. The ability to maintain customer SLAs in case of a network failure. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view.The It describes current metro, which isuse based on TDM resources, technology, and discusses the ability tothe achieve the most efficient of network in a way that provides drivers and challenges carriers willwith face their in transforming good QoS that meets an SLA customers. the metro to address data services. MetroThe Ethernet the adoption ofametro Ethernet services and how that has led carriers abilitydiscusses to restore failure within timeline that does not violate any SLAs they to the delivery of metro data services. With a changing mix of transport technologies, the book established with their customers. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual area (VLAN), virtual privatein LAN (VPLS), traffic to Because MPLS private plays alocal big role innetworks delivering and scaling services theservices metro, it is important engineering, and MPLS and Generalized MPLS (GMPLS). understand how it can be used to achieve TE and protection via the use of RSVP-TE. In this chapter, you see how MPLS, through the use of RSVP-TE, can be used to establish backup paths in the case of failure.

Understanding RSVP-TE
MPLS TE may be used to divert traffic over an explicit route. The specification of the explicit route is done by enumerating an explicit list of the routers in the path. Given this list, TE trunks can be constructed in a variety of ways. For example, a trunk could be manually configured • Table of Contents along the explicit path. This involves configuring each router along the path with state • Index information for forwarding the particular MPLS label.
Metro Ethernet

Alternately, BySam Halabi a signaling protocol such RSVP-TE can be used with an EXPLICIT_ROUTE object (ERO) so that the first router in the path can establish the trunk. The ERO is basically a list of router IP addresses.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

NOTE
Constraint-based routing LDP (CR-LDP) is another signaling protocol that can be used to build traffic-engineered paths. However, the use of RSVP-TE is more widely deployed and as such will be discussed in this book. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and Originally, RSVP (defined RFC 2205, Resource ReSerVation Protocol—Version 1 Functional what they can do forin your organization Specification) was designed as a protocol to deliver QoS in the network by allowing routers to establish resource reservation state for individual flows originated professionals between hosts (computers). Learn from the easy-to-read format that enables networking of all levels to This model has not taken off with network operators because of scalability issues in maintaining understand the concepts the per-flow state between pairs of hosts in each router along the IGP path. The RSVP implementation is illustrated in of Figure 6-1. Gain from the experience industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Figure 6-1 illustrates two RSVP sessions between andthe B and C and D. The routers then examines current and emerging trends, and hosts delvesA into rolehosts of virtual private networks in the path would have to maintain state information for these sessions to allocate certain (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic bandwidth toand the MPLS individual With a large(GMPLS). number of hosts (millions) in a public network, engineering, and flows. Generalized MPLS this model has not proven to be efficient and hence has not been adopted in the public Internet. In the late 1990s, RSVP was extended to support the creation of MPLS label switched paths (LSPs). The extended RSVP implementations introduced a lot of changes to the traditional RSVP, to support scalability issues and TE. In particular, RSVP sessions take place between ingress and egress label switch routers (LSRs) rather than individual hosts. The aggregated traffic flow,

Figure 6-1. Original RSVP Implementation

called a traffic trunk, is then mapped to LSPs, also called LSP tunnels . The RSVP-TE implementation is shown in Figure 6-2.

Figure 6-2. RSVP-TE Implementation

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The extensions of RSVP to support MPLS and TE can accomplish the following: Establish a forwarding path— RSVP can be used to establish LSPs by exchanging label information. This mechanism is similar to the Label Distribution Protocol (LDP). The definitive guide to Enterprise and Carrier Metro Ethernet applications. Establish an explicit path— RSVP-TE is used to establish an LSP along an explicit route according to specific constraints. LSPs can be rerouted upon failure. (Fast reroute is Discover the latest developments in metro networking, Ethernet, and MPLS services and discussed later, in the section "Understanding MPLS Fast Reroute.") what they can do for your organization Resource reservation— The existing RSVP procedures for resource reservation can be Learn from the easy-to-read format that enables networking professionals of all levels to applied on aggregated flows or traffic trunks. This model scales because it is done on understand the concepts trunks rather than flows and is done between pairs of routers rather than pairs of hosts, as was intended for RSVP. Gainoriginally from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures The reason IETF chose to extend RSVP to support MPLS and TE has to do with the fact that RSVP was originally designed for resource reservation in the Internet, a concept industry that is closely tied to Metro networks will emerge as the next area of growth for the networking and will TE, so it makes sense to extend the protocol rather than create a new one. RSVP also can carry represent a major shift in how data services are offered to businesses and residential customers. opaque objects such as fields that can be delivered to routers, which makes it easy to define The metro has always been a challenging environment for delivering data services because itnew has objects for to different Thereliability purpose of some of theseneeds objects isvoice. to carry labelswill for have the to been built handle purposes. the stringent and availability for Carriers label distribution function, whereas the the purpose offor others is to create explicit routes. go through fundamental shifts to equip metro next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the The following sections describe how RSVP tunnels are created and the mechanisms that are used operational and business model that will allow the incumbent carriers to transform the metro to to exchange MPLS labels and reserve bandwidth: offer enhanced data services. MetroRSVP Ethernet Cisco Press looks at the deployment of metro data services from a holistic LSP from Tunnels view. It describes the current metro, which is based on TDM technology, and discusses the drivers andBinding challenges will face in transforming the metro to address data services. Label andcarriers LSP Tunnel Establishment Via RSVP MetroReservation Ethernet discusses Styles the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines and emerging trends, and delves into the role of virtual private networks Details of current the PATH Message (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, Details of and the MPLS Reservation and Generalized Message MPLS (GMPLS).

RSVP LSP Tunnels
Service providers create LSP tunnels to aggregate traffic belonging to the same forwarding

equivalency class. You have seen in Chapter 4, "Hybrid L2 and L3 in IP/MPLS Networks," that multiple Virtual Private LAN Services (VPLSs) can be carried over a single LSP tunnel across the network. LSPs are called LSP tunnels because the traffic going through an LSP tunnel is opaque to the intermediate LSRs between the ingress and egress LSRs. Figure 6-3 shows the establishment of an LSP tunnel between an ingress LSR and an egress LSR that is peering with multiple providers. Notice how the LSP tunnel is formed using two unidirectional tunnels in both directions.
• • Table of Contents Index
Metro Ethernet BySam Halabi

Figure 6-3. LSP Tunnel Between Ingress and Egress LSRs

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization InFigure 6-3, traffic coming into router A and transiting the service provider's network toward other Learn service providers' networks, format such as ISP enables 1, ISP 2, and ISP 3,professionals can all be grouped in theto from the easy-to-read that networking of all levels sameunderstand forwarding the equivalency conceptsclass. This class is defined by all traffic destined for the exit router with IP address 10.10.10.10. In this case, all traffic toward 10.10.10.10 is tagged with the same Gain label from at the experience of industry innovator and best-selling Cisco Press author, Sam outbound router A. This maps all transit traffic toward the same LSP tunnel. Halabi, author of Internet Routing Architectures The exit point for a given external route (10.10.10.10) is normally learned via the Internal Metro networks emerge as the nextthe area of growth forthe the networking and will Border Gatewaywill Protocol (IBGP). After traffic reaches exit router, itindustry is sent to the correct represent a major in how data services ISP, depending on shift the final external route. are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Label Binding and LSP Tunnel Establishment Via RSVP by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to RFC RSVP-TE: Extensions to RSVP for LSP Tunnels, defines the capabilities of extended offer 3209, enhanced data services. RSVP. Regarding the operation of LSP tunnels, extended RSVP enables you to do the following: Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Perform downstream-on-demand allocation, distribution, binding. drivers and challenges carriers will facelabel in transforming the metro toand address data services. the actual route traversed an established LSP tunnel. MetroObserve Ethernet discusses the adoption ofby metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Identify and diagnose LSP tunnels. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local with area or networks virtual private LAN services (VPLS), traffic Establish LSP tunnels without(VLAN), QoS requirements. engineering, and MPLS and Generalized MPLS (GMPLS). Dynamically reroute an established LSP tunnel. Preempt an established LSP tunnel under administrative policy control. To establish an LSP tunnel, the ingress LSR sends a PATH message to the egress LSR, which in

turn replies with a reservation message (RESV). Upon completion of the handshake, an LSP tunnel is established. The PATH message indicates the PATH that the LSP should take, and the RESV message attempts to establish a bandwidth reservation following the opposite direction of the PATH message. PATH and RESV messages are explained in detail in the sections "Details of the PATH Message" and "Details of the RESV Message," respectively. RSVP-TE has defined new objects in support of creating LSP tunnels. These new objects, called LSP_TUNNEL_IPv4 and ISP_Tunnel_IPv6, help, among other things, identify LSP tunnels. The • Table of Contents SESSION object, for instance, carries a tunnel ID, while the SENDER_TEMPLATE and • Index FILTER_SPEC objects uniquely identify an LSP tunnel.
Metro Ethernet BySam The following Halabi is the sequence of events needed to establish an LSP tunnel:

Publisher: Cisco Press Date: October 01,node 2003 on the path—that is, the ingress LSR (sender)—creates an RSVP PATH 1.Pub The first MPLS ISBN: 1-58705-096-X message with a session type of LSP_TUNNEL_IPv4 or LSP_TUNNEL_IPv6 and inserts a LABEL_REQUEST Pages: 240 object into the PATH message.

2. The LABEL_REQUEST object indicates that a label binding for this path is requested and also indicates the network layer protocol that is to be carried over this path. In addition to the LABEL_REQUEST object, the PATH message can carry a number of The definitive guide to Enterprise and Carrier Metro Ethernet applications. optional objects: -EXPLICIT_ROUTE object (ERO)— Specifies a predetermined path between the Discover the latest developments in metro networking, Ethernet, and MPLS services and ingress and egress LSRs. When the ERO object is present, the PATH message is sent what they can do for your organization toward the first node indicated by the ERO, independent of the IGP shortest path. Learn from the easy-to-read format that enables networking professionals of all levels to -RECORD_ROUTE understand the concepts object (RRO)— Used to record information about the actual route taken by the LSP. This information can be relayed back to the sender node. The sender node can also this object to request notification fromPress the network Gain from the experience ofuse industry innovator and best-selling Cisco author, Sam concerning in the routing path. Halabi, author of changes Internet Routing Architectures -SESSION_ATTRIBUTE object— Can be added tonetworking PATH messages to help Metro networks will emerge as the next area of growth for the industry and in will identification and diagnostics. Additional control information, such customers. as setup represent asession major shift in how data services are offered to businesses and residential and always hold priorities and local protection, is also in data this object. The metro has been a challenging environment for included delivering services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded 3. The labelcustomers allocation and with RSVP is done using the downstream-on-demand by enterprise consumers. This is not only a technology shift, butlabel also assignment a shift in the mechanism. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. 4. The RESV message is sent back upstream toward the sender, following the path created by PATH message, inPress reverse order. Metrothe Ethernet from Cisco looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the 5. Each node that receives an RESV message containing LABEL object uses that label for drivers and challenges carriers will face in transforming thea metro to address data services. outgoing traffic associated with this LSP tunnel. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers When the of RESV message arrives at theaingress LSR, the tunneltechnologies, is established. to6. the delivery metro data services. With changing mix ofLSP transport the book then examines current and emerging trends, and delves into the role of virtual private networks This process is illustrated in Figure 6-4. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 6-4. Establishing an LSP Tunnel

• •
Metro Ethernet

Table of Contents Index

InFigure 6-4, ingress LSR A sends a PATH message toward LSR C with a session type object and BySam Halabi an ERO. The ERO contains the explicit route that the PATH message needs to take. The ERO in this case is the set {B,C}, which dictates the path to be taken via LSR B, then LSR C.
Publisher: Cisco Press

In turn, LSR B propagates Pub Date: October 01, 2003 the PATH message toward LSR C according to the ERO. When LSR C receives the PATH message, it sends an RESV message that takes the reverse PATH indicated in ISBN: 1-58705-096-X the ERO toward Pages: 240 LSR A. LSR C includes an inbound label of 10. Label 10 is used as an outbound label in LSR B. LSR B sends an RESV message toward LSR A with an inbound label of 5. Label 5 is used as an outbound label by LSR A. An LSP tunnel is formed between LSRs A and C. All traffic that is mapped to this LSP tunnel is tagged with label 5 at LSR A. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Reservation Styles

Discover the latest developments in metro networking, Ethernet, and MPLS services and The existing RSVP procedures for resource reservation can be applied on aggregated flows or what they can do for your organization traffic trunks. This model scales because it is done on trunks rather than flows and between pairs of routers rather than pairs of hosts, as was originally intended for RSVP. The receiver node can Learn the format that enables networking professionals of all levels to select from from among a easy-to-read set of possible reservation styles for each session, and each RSVP session understand the concepts must have a particular style. Senders have no influence on the choice of reservation style. The receiver can choose different reservation styles for different LSPs. Bandwidth reservation is not Gain from the experience of industry innovator and best-selling Cisco Press author, Sam mandatory for the operation of RSVP-TE. It is up to the service provider to engineer the Halabi, author of Internet Routing Architectures networks as necessary to meet the SLAs. Metro networks will emerge as the next area of growth for the networking industry and will The following sections discuss the different reservation styles listed here and their advantages represent a major shift in how data services are offered to businesses and residential customers. and disadvantages: The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Fixed Filter (FF) by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business Shared Explicit (SE) model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Wildcard Filter (WF) Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Fixed Filter Reservation Style Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers The FFdelivery reservation style data creates a distinct reservation for traffic from each sender. This style is to the of metro services. With a changing mix of transport technologies, the book normally used for applications whose trends, traffic from sender is independent ofprivate other senders. then examines current and emerging and each delves into the role of virtual networks The total amount of reserved bandwidth on a link for sessions using FF is the sum of the (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic reservations for the individual senders. Because each sender has its own reservation, a unique engineering, and MPLS and Generalized MPLS (GMPLS). label is assigned to each sender. This can result in a point-to-point LSP between every sender/receiver pair. An example of such an application is a one-on-one videoconferencing session. Bandwidth reservations between different pairs of senders and receivers are independent of each other. InFigure 6-5, ingress LSRs A and B create distinct FF-style reservations toward LSR D. The total

amount of bandwidth reserved on link C-D is equal to the sum of reservations requested by A and B. Notice also that LSR D has assigned different labels in the RESV messages toward A and B. Label 10 is assigned for sender A, and label 20 is assigned for sender B. This creates two distinct point-to-point LSPs—one between A and D and the other between B and D.

Figure 6-5. Fixed Filter Reservation Style
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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Shared Explicit Reservation Style
Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can style do for your organization The SE reservation allows a receiver to explicitly select a reservation for a group of senders—rather than one reservation per sender, as in the FF style. Only a single reservation is Learn from the easy-to-read format that enables networking professionals of all levels to shared between all senders listed in the particular group. understand the concepts SE style reservations can be provided using one or more multipoint-to-point LSPs per sender. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Multipoint-to-point LSPs may be used when PATH messages do not carry the ERO, or when PATH Halabi, author of Internet Routing Architectures messages have identical EROs. In either of these cases, a common label may be assigned. Metro networks will emerge as the next area of growth for the networking industry and will PATH messages from different senders can each carry their own ERO, and the paths taken by the represent a major shift in how data services are offered to businesses and residential customers. senders can converge and diverge at any point in the network topology. When PATH messages The metro has always been a challenging environment for delivering data services because it has have differing EROs, separate LSPs for each ERO must be established. Figure 6-6 explains the SE been built to handle the stringent reliability and availability needs for voice. Carriers will have to style even further. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Figure 6-6. Shared Explicit Reservation operational and business model that will allow the incumbent carriers toStyle transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

InFigure 6-6, LSRs A and B are using the SE style to establish a session with LSR D. The reservation for link C-D is shared between A and B. In this example, both PATH messages coming from A and B have the same ERO and are converging on node C. Notice that D has allocated a single label 10 in its RESV message, hence creating the multipoint-to-point LSP. An example of such an application is a videoconferencing session between multiple branch offices in Europe and the main office in the United States. The bandwidth reserved on the international link is set for a certain amount, and the number of remote branch offices is set in a way that the • of Contentsused by the branch offices does not exceed the total reserved total amountTable of bandwidth • Index bandwidth.
Metro Ethernet BySam Halabi

Wildcard Filter Reservation Style
Publisher: Cisco Press

A third reservation style Pub Date: October 01, 2003 that is defined by RSVP is the WF reservation style. Unlike the SE style, where ISBN: the receiver indicates the specific list of senders that are to share a reservation, with the 1-58705-096-X WF reservation Pages: 240 style, a single shared reservation is used for all senders to a session. The total reservation on a link remains the same regardless of the number of senders. This style is useful for applications in which not all senders send traffic at the same time. If, however, all senders send simultaneously, there is no means of getting the proper reservations made. This restricts the applicability of WF for TE purposes. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Furthermore, because of the merging rules of WF, EROs cannot be used with WF reservations. This is another reason that prevents the use of the WF style for traffic engineering. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

Details of the PATH Message Learn from the easy-to-read format that enables networking professionals of all levels to
understand the concepts The PATH message can include several different RSVP objects, including the following: Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures LABEL_REQUEST Metro networks will emerge as the next area of growth for the networking industry and will represent EXPLICIT_ROUTE a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been RECORD_ROUTE built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded SESSION_ATTRIBUTE by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer FLOW_SPEC enhanced data services. MetroSENDER_TEMPLATE Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the SESSION drivers and challenges carriers will face in transforming the metro to address data services. Figure 6-7 shows the format of the PATH message. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Figure 6-7. RSVP-TE PATH then examines current and emerging trends, and delves into Message the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. The following sections describe each object in more detail. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

LABEL_REQUEST Object

Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts The LABEL_REQUEST object is used to establish label binding for a certain path. It also indicates the network layer protocol that is to be carried over this path. The reason for this is that the Gain from the experience of industry innovator and best-selling Cisco Press author,be Sam network layer protocol sent down an LSP does not necessarily have to be IP and cannot Halabi, author of Internet Routing Architectures deduced from the L2 header, which only identifies the higher-layer protocol as MPLS. The LABEL_REQUEST object has three possible C_Types (Class_Types): Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro always been awithout challenging environment for is delivering data services it has Type has 1, label request label range— This a request for a regularbecause 32-bit MPLS been label built to handle the stringent reliability and availability needs for voice. Carriers will have to that sits in the shim layer between the data link and network layer headers. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise Type 2, customers label request and consumers. with an ATM This label is not range— only a This technology request shift, specifies but also the minimum a shift in the operational and maximum and business virtual model path that identifier will allow (VPI)the and incumbent virtual connection carriers to identifier transform (VCI) the values metro to offer that enhanced are supported data services. on the originating switch. This is used when the MPLS label is carried in an ATM header. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view.Type It describes 3, label the request currentwith metro, Frame which Relay is based label on range— TDM technology, This request and specifies discusses the the drivers minimum and challenges and maximum carriersdata-link will face connection in transforming identifier the metro (DLCI) tovalues address that data are services. supported on the originating switch. This is used when the MPLS label is carried in a Frame Relay header. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the the When delivery PATHof message metro data reaches services. an LSR, With the a changing LABEL_REQUEST mix of transport object gets technologies, stored in the the path book then examines state block for further currentuse andby emerging refresh messages. trends, and When delves the into PATH themessage role of virtual reaches private the receiver, networks (VPN), the presence virtualof private a LABEL_REQUEST local area networks object (VLAN), triggers virtual the receiver private to LAN allocate services a label (VPLS), and to traffic place engineering, the label in the and LABEL MPLS object and Generalized for the corresponding MPLS (GMPLS). RESV message. If a label range is specified, the label must be allocated from that range. Error messages might occur in cases where the receiver cannot assign a label, cannot recognize the protocol ID, or cannot recognize the LABEL_REQUEST object.

EXPLICIT_ROUTE Object
The EXPLICIT_ROUTE object (ERO) is used to specify an explicit path across the network independent of the path specified by the IGP. The contents of an ERO are a series of variablelength data items called subobjects. A subobject is an abstract node that can be either a single node or a group of nodes such as an autonomous Table system. This means that the explicit path can cross multiple autonomous systems, • of Contents and the hopsIndex within each autonomous system are opaque (hidden) from the ingress LSR for that • path. Ethernet Metro
BySam Halabi

The subobject contains a 1-bit Loose Route field (L). If set to 1, this field indicates that the subobject is a loose hop in the explicit path, and if set to 0, it indicates that the subobject is a Publisher: Cisco Press strict hop. A strict hop indicates that this hop is physically adjacent to the previous node in the Pub Date: October 01, 2003 path.
ISBN: 1-58705-096-X

The subobject Pages: 240 also contains a Type field, which indicates the types of the content subobjects. Some defined values of the Type field are as follows: 1: IPv4 Prefix— Identifies an abstract node with a set of IP prefixes that lie within this IPv4 prefix. A prefix of length 32 is a single node (for example, a router's IP loopback The definitive guide to Enterprise and Carrier Metro Ethernet applications. address). 2: IPv6 Prefix— Identifies an abstract node with a set of IP prefixes that lie within this Discover theA latest developments networking, Ethernet, a and MPLS IP services and IPv6 prefix. prefix of length 128in is metro a single node (for example, router's loopback what they can do for your organization address). Learn from the easy-to-read format that enables an networking professionals of of allthe levels 32: Autonomous System number— Identifies abstract node consisting set to of understand the concepts nodes belonging to the autonomous system. Gain from of industry innovator best-selling Press author, Sam Figures 6-8 andthe 6-9experience illustrate two scenarios in which and an explicit path Cisco is being established using Halabi, author of Internet Routing Architectures strict and loose subobjects, respectively, of the Type IPv4 prefix and with a subobject length of 32. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Figure 6-8. Explicit Route, Strict Hops The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 6-9. Explicit Route, Loose Hops

• •
Metro Ethernet BySam Halabi

Table of Contents Index

InFigure 6-8, ingress LSR A sends a PATH message toward LSR D with an ERO that indicates a Pub Date: October 01, 2003 strict hop across routers B (192.213.1.1), C (192.213.2.1), and D (192.213.3.1). When B ISBN: 1-58705-096-X receives the PATH message, it propagates it toward C, and C propagates the message toward D. Pages: 240 In turn, D sends a RESV message to A along the same path, and the label binding takes place. The ERO itself is modified at each hop. Each node in the ERO list removes itself from the ERO as the PATH message is forwarded. InFigure 6-9, ingress LSR A sends a PATH message toward LSR D with an ERO that indicates a strict hop toward B. to From router B, a loose hop is used. When router B receives the PATH The definitive guide Enterprise and Carrier Metro Ethernet applications. message, it would send the PATH message to D along any available route. In this example, there are two possible routes toward D—one via a direct connection to C and the other via router E. Discover the latest in on metro Ethernet, and MPLS services and The way the loose hop isdevelopments picked depends the networking, IGP route that is available toward D. what they can do for your organization It is important to note that intermediate LSRs between the sender and receiver may also change Learn the easy-to-read format that is enables professionals of all a levels to the ERO by from inserting subobjects. An example where networking an intermediate node replaces loose the a concepts routeunderstand subobject with strict route subobject to force the traffic around a specific path. Also, the presence of loose nodes in an explicit route implies that it is possible to create forwarding loops Gain from the experience of industry innovator Loops and best-selling Cisco Press author, Sam in the underlying routing protocol during transients. in an LSP tunnel can be detected Halabi, author of Internet Routing Architectures using the RECORD_ROUTE object (RRO), as discussed in the next section. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. RECORD_ROUTE Object The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to The RRO is used to collect detailed paththe information is useful for loop detection for go through fundamental shifts to equip metro forand next-generation data services and demanded diagnostics. By adding an RRO to the PATH message, thea sender can receive information about by enterprise customers and consumers. This is not only technology shift, but also a shift in the the actual PATH taken by model the LSP. Remember although the ERO specifies an explicit PATH, operational and business that will allow that the incumbent carriers to transform the metro to the PATH mightdata contain loose hops, and some intermediate nodes might change the ERO, so the offer enhanced services. final PATH recorded by the RRO could be different from the ERO specified by the sender. The RRO can be present both RSVP PATH and messages. The RRO presentfrom in an Metro Ethernet fromin Cisco Press looks at theRESV deployment of metro datais services aRESV holistic message if the RRO that has been recorded on the PATH message needs to be returned the to the view. It describes the current metro, which is based on TDM technology, and discusses ingress LSR. drivers and challenges carriers will face in transforming the metro to address data services. There are threediscusses possible uses of RROs in Metro Ethernet the adoption of RSVP: metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks Loop detection— An area RRO networks can function as a loop-detection to discover L3 (VPN), virtual private local (VLAN), virtual private mechanism LAN services (VPLS), traffic routing loops or loops inherent in the explicit route. engineering, and MPLS and Generalized MPLS (GMPLS). Path information collection— An RRO collects up-to-date detailed path information hopby-hop about RSVP sessions, providing valuable information to the sender or receiver. Any path change (because of network topology changes) is reported. Feedback into ERO— An RRO can be used as input to the ERO object. If the sender

Publisher: Cisco Press

receives an RRO via the RESV message, it can alter its ERO in the next PATH message. This can be used to "pin down" a session path to prevent the path from being altered even if a better path becomes available. The initial RRO contains only one subobject: the sender's IP addresses. When a PATH message containing an RRO is received by an intermediate router, the router stores a copy of it in the path state block. When the PATH message is forwarded to the next hop, the router adds to the RRO a new subobject that contains its own IP address. When the receiver sends the RRO to the • Table of Contents sender via the RESV message, the RRO has the complete route of the LSP from ingress to • Index egress.
Metro Ethernet BySam Halabi

SESSION_ATTRIBUTE Object
Publisher: Cisco Press Date: October 01, 2003 object allows RSVP-TE to set different LSP priorities, preemption, and ThePub SESSION_ATTRIBUTE ISBN: 1-58705-096-X fast-reroute features. These are used to select alternate LSPs in case of a failure in the network. The SESSION_ATTRIBUTE Pages: 240 is carried in the PATH message. It includes fields such as Setup Priority and Holding Priority, which affect whether this session can preempt or can be preempted by other sessions. A Flag field is also used to introduce options such as whether transit routers can use local mechanisms that would violate the ERO and cause local repair. Other Flag options indicate that the tunnel ingress node may choose to reroute this tunnel without tearing it down.

The definitive guide to Enterprise and Carrier Metro Ethernet applications.

FLOW_SPEC Object
Discover the latest developments in metro networking, Ethernet, and MPLS services and what theyRSVP can do for your organization An elementary reservation request consists of a FLOW_SPEC together with a FILTER_SPEC; this pair is called a flow descriptor. The FLOW_SPEC object specifies a desired Learn from the easy-to-read format that enables networking professionals of all levels to QoS. The FILTER_SPEC object, together with a SESSION object specification, defines the set of understand the concepts data packets—the "flow"—to receive the QoS defined by the flowspec. An example of the use of FLOW_SPEC with RSVP-TE would to indicate which path certain traffic gets put on based on Gain from the experience of be industry innovator and best-selling Cisco Press author, Sam the QoS characteristics of such traffic. Data packets that are addressed to a particular session Halabi, author of Internet Routing Architectures but that do not match any of the filter specs for that session are handled as best-effort traffic. The flowspec in a reservation request generally a service class and two sets of numeric Metro networks will emerge as the next area of includes growth for the networking industry and will parameters: represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to An Rspec (R for "reserve") that defines the desired QoS go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and that consumers. This isdata not only A Tspec (T for "traffic") describes the flow a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.

SENDER_TEMPLATE Object Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic
view. It describes the current metro, which is based on TDM technology, and discusses the drivers PATH messages and challenges are required carriers towill carry face a SENDER_TEMPLATE in transforming the metro object,to which address describes data services. the format of data packets that this specific sender originates. This template is in the form of a FILTER_SPEC Metro the adoption of metro Ethernet services that has led that isEthernet typically discusses used to select this sender's packets from others inand the how same session on carriers the same to the delivery of metro data services. With a changing mix of transport technologies, the book link. The extensions of RSVP for TE define a new SENDER_TEMPLATE C-Type then examines current and emerging and delves into the role of virtual private16-bit networks (LSP_TUNNEL_IPv4) that contains thetrends, IPv4 address for the sender node and a unique (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic identifier, the LSP_ID, that can be changed to allow a sender to share resources with itself. This engineering, and MPLS and Generalized MPLS (GMPLS). LSP_ID is used when an LSP tunnel that was established with an SE reservation style is rerouted.

SESSION Object
The SESSION object is added to the PATH message to help identify and diagnose the session.

The new LSP_TUNNEL_IPv4 C-Type contains the IPv4 address of the tunnel's egress node and a unique 16-bit identifier that remains constant over the life of the LSP tunnel, even if the tunnel is rerouted.

Details of the RESV Message
• Table of Contents An RESV message is transmitted from the egress LSR toward the ingress in response to the • Index receipt of a PATH message. The RESV message is used for multiple functions, including:
Metro Ethernet distributing label

bindings, requesting resource reservations along the path, and specifying the reservation BySam Halabi style (FF or SE). The RSVP RESV message can contain a number of different objects such as LABEL, Publisher: Cisco Press RECORD_ROUTE, SESSION, and STYLE.
Pub Date: October 01, 2003

Figure ISBN: 6-101-58705-096-X shows the format of the RESV message.
Pages: 240

Figure 6-10. RSVP-TE RESV Message

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded The RECORD_ROUTE and SESSION objects were described as part of the PATH message in the by enterprise customers and consumers. This is not only a technology shift, but also a shift in the preceding section. The LABEL object contains the label or stack of labels that is sent from the operational and business model that will allow the incumbent carriers to transform the metro to downstream node to the upstream node. The STYLE object specifies the reservation style used. offer enhanced data services. As you have learned, the FF and SE reservation styles filters are used for TE. For the FF and SE styles, a label is provided for each sender to the LSP. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Understanding MPLS Fast Reroute
One of the requirements for TE is the capability to reroute an established TE tunnel under various conditions. Such rerouting capabilities could include the following:
• • Table of Contents

Setting Index administrative policies to allow the LSP to reroute, such as when the LSP does not QoS requirements. Metro meet Ethernet
BySam Halabi

Rerouting an LSP upon failure of a resource along the TE tunnel's established path. policy that might require that an LSP that has been rerouted path when a failed link or router becomes available.

Publisher: Cisco Setting an Press administrative Pub must Date:return October to 01,its 2003 original ISBN: 1-58705-096-X

Network operation must not be disrupted while TE rerouting is in progress. This means that you Pages: 240 need to establish backup tunnels ahead of time and transfer traffic from the old tunnel to the new tunnel before you tear down the old tunnel. This concept is called make-before-break. A problem could arise if the old and new tunnels are competing for network resources; this might prevent the new tunnel from being established, because the old tunnel that needs to be torn down still has the allocated resources. The definitive guide to Enterprise and Carrier Metro Ethernet applications. One of the advantages of using RSVP-TE is that the protocol has many hooks to take care of such problems. RSVP uses the SE reservation style to prevent the resources used by an old tunnel the latest in is metro networking, Ethernet, and MPLS services and from Discover being released untildevelopments the new tunnel established. The SE reservation style also prevents what they can do for your organization double counting of the resources when moving from an old tunnel to a new tunnel. Learnof from the easy-to-read format that enables networking professionals of applications all levels to in The speed rerouting a failed tunnel is crucial for maintaining SLAs for real-time understand the concepts the metro. When an LSP tunnel fails, the propagation of the failure to the ingress LSR/LER that established the tunnel and the convergence of the network to a new LSP tunnel could cause Gain from the experience of industry innovator and best-selling Cisco Press author, Sam higher-level applications to time out. MPLS fast reroute allows an LSP tunnel to be rerouted in Halabi, author of Internet Routing Architectures tens of milliseconds. Metro networks will emerge as the next area of growth for the networking industry and will RSVP-TE can be used to establish backup LSP tunnels if active LSP tunnels fail. There are two represent a major shift in how data services are offered to businesses and residential customers. methods of doing so: The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental End-to-end repair shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Local repair offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic End-to-End Repair view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. With the end-to-end repair method, the whole LSP tunnel is backed up from the ingress LSR to Metro Ethernet adoption of metro Ethernet how that the egress LSR.discusses If the LSPthe fails because of a break in the services network,and a whole new has LSP led is carriers to the delivery of metro data services. With a changing mix of transport technologies, theis book established end to end. In this case, it is possible to presignal the secondary path, which then examines current and emerging trends, and delves into the role of virtual private networks quicker than resignaling the LSP. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Local Repair
Local repair allows the LSP to be repaired at the place of failure. This allows the existing LSP to reroute around a local point of failure rather than establish a new end-to-end LSP. The benefit of

repairing an LSP at the point of failure is that it decreases the network convergence time and allows the traffic to be restored in tens of milliseconds. This is important to meet the needs of real-time applications such as Voice over IP or video over IP, which are the next-generation services for metro networks. To achieve restoration in tens of milliseconds, backup LSPs are signaled and established in advance of failure. The traffic is also redirected as close to the failure as possible. This reduces the delays caused by propagating failure notification between LSRs.
• Table of Contents • Index the difference between using local repair and end-to-end repair. Figure 6-11 shows
Metro Ethernet BySam Halabi

Figure 6-11. The Value of Local Repair

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures InFigure 6-11, an LSP tunnel is established between R1 and R5. If end-to-end repair is used and Metro networks will emerge the next area of growth for R1 the networking industry and a failure occurs anywhere onas the links or routers between and R5—the R3-R4 link in will this represent a major shift in how data services are offered to the businesses andAlso, residential example—failure notification has to propagate from R3 all way to R1. all the customers. LSRs, The metro has always beento a be challenging environment for delivering data services because it has including R1 and R2, have involved in recomputing the new path. If the secondary path is been built to handle the reliability and availability needs for voice. Carriers will have to presignaled between R1 stringent and R5, convergence occurs much faster. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise Conversely, local customers repair allows and consumers. the traffic This to be is redirected not only aclosest technology to the shift, failure but and also hence a shift in the operational and dramatically reduces business the restoration model that time. will allow If local therepair incumbent is used, carriers the LSP to transform could be spliced the metro to offer enhanced between R3 and data R5, services. bypassing the failure. Of course, this is all great as long as you know where the failure will occur so that you can work around it. Because this is impossible to know, you Metroto Ethernet Cisco looks at the deployment of metro data services from a holistic have predict from which links Press are carrying critical data and need to be protected. Two local repair view. It describes the current metro, which backup, is basedare on TDM technology, techniques, one-to-one backup and facility discussed next. and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers One-to-One Backup to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks In the one-to-one backup a node (VLAN), is protected against a failure on its downstream link or (VPN), virtual private localmethod, area networks virtual private LAN services (VPLS), traffic node by creating LSP that starts upstream that node and intersects with the original LSP engineering, and an MPLS and Generalized MPLS of (GMPLS). somewhere downstream of the point of link or node failure. In Figure 6-11 (local repair) the oneto-one backup method was used to protect against a failure of the link R3-R4, or the failure of node R4. In this case, R3's backup is an LSP that starts at R3 and ends downstream of the R3-R4 link on the R5 node. The partial LSP that starts from R3 and goes around R4 and splices back into the original LSP is called a detour LSP . To fully protect an LSP that passes N nodes, there

could be as many as N–1 detours. In the example in Figure 6-12, to protect the LSP between R1 and R5, there could be as many as four detour LSPs.

Figure 6-12. Full LSP Protection

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The LSP that needs to be protected is R1-R2-R3-R4-R5: Upon failure of the R1-R2 link, or R2 node, R1's detour LSP would be R1-R6-R7-R8-R3. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Upon failure of the R2-R3 link, or R3 node, R2's detour LSP would be R2-R7-R8-R4. Upon failure the R3-R4 link, or in R4metro node, networking, R3's detour Ethernet, LSP wouldand be R3-R8-R9-R5. Discover the of latest developments MPLS services and what they can do for your organization Upon failure of the R4-R5 link, R4's detour LSP would be R4-R9-R5. Learn from the easy-to-read format that enables networking professionals of all levels to The point (router) that initiates the detour LSP is called the point of local repair (PLR). When a understand the concepts failure occurs along the protected LSP, the PLR redirects the traffic onto the local detour. If R1R2 fails, R1 switches the traffic of into the detour LSP R1-R6-R7-R8-R3. Gain from the experience industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will Facility Backup—Bypass represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data backup. servicesInstead because it has Another method for protecting the LSP against failure is called the facility of been built to handle the stringent reliability and availability needs for voice. Carriers will have to creating a separate LSP for every backed-up LSP, a single LSP is created that serves to back up a go through fundamental shifts to equip the metro for next-generation data services demanded set of LSPs. This LSP is called a bypass tunnel. The bypass tunnel intersects the path of the by enterprise customers and consumers. This is not in only a technology shift, but also a shift in the original LSPs downstream of the PLR. This is shown Figure 6-13. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.

Figure 6-13. Bypass Tunnel

Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The bypass tunnel R2-R6-R7-R4 is established between R2 and R4. The scalability improvement The definitive guide comes to Enterprise and Carrier Metro Ethernet applications. from this technique from the fact that this bypass tunnel can protect any LSP from R1, R2, and R8 to R4, R5, and R9. As with the one-to-one technique, to fully protect an LSP that traverses N nodes, there could be as many as N–1 bypass tunnels. However, each of these Discover the latest developments in metro networking, Ethernet, and MPLS services and bypass tunnels can protect a set of LSPs. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
This chapter has discussed the basics of RSVP-TE and how it can be applied to establish LSPs, bandwidth allocation, and fast-reroute techniques. A detailed explanation of the RSVP-TE messages and objects was offered to give you a better feel for this complex protocol, which • Table of probably requires a Contents book of its own. Many of the techniques explained in this chapter apply to • Index provisioning scalable L2 metro Ethernet services.
Metro Ethernet

The metro BySam Halabiwill consist of a mix of technologies ranging from Ethernet switches to SONET/SDH equipment to optical switches. Creating a unified control plane that is capable of provisioning LSP tunnels end to end and helping in the configuration and management of such equipment Publisher: Cisco Press becomes crucial. You have seen the MPLS control plane used for packet networks. The flexibility Date: October 01, 2003 andPub standardization of MPLS is extending its use to TDM and optical networks. The next two ISBN: 1-58705-096-X chapters discuss Generalized MPLS (GMPLS) and how this control plane becomes universal in Pages: 240 adapting not only to packet networks but also across TDM and optical networks.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 7. MPLS Controlling Optical Switches
• of Contents This chapter Table covers the following topics: •
Metro Ethernet BySam Halabi

Index

Understanding GMPLS Establishing the Need for GMPLS

Publisher: Cisco Press

Signaling Models Pub Date: October 01, 2003 Label Switching in a Nonpacket World
Pages: 240 ISBN: 1-58705-096-X

The operation of today's optical networks is manual and operator-driven, which increases network operational complexities and cost. The industry has been looking for methods that reduce the operational burden of manual circuit provisioning, reduce costs, and offer a more dynamic response to customer requirements. In other words, the industry wants to be able to The definitive deploy time-division guide to multiplexing Enterprise and (TDM) Carrier and optical Metro Ethernet circuits more applications. dynamically and wants faster provisioning times. Discover upon the latest developments in metro networking, Ethernet, and MPLSto services and The principles which MPLS technology is based are generic and applicable multiple what they can do for your organization layers of the transport network. As such, MPLS-based control of other network layers, such as the TDM and optical layers, is also possible. The Common Control and Measurement Plane Learn from the easy-to-read format that enables networking professionals of all levels to (CCAMP) Working Group of the IETF is currently working on extending MPLS protocols to support understand the concepts multiple network layers and new TDM and optical services. This concept, which was originally referred to as Multiprotocol Lambda Switching (MPl S), is now referred to as Generalized MPLS Gain This fromchapter the experience industry innovator and best-selling Cisco Press author, Sam (GMPLS). refers toof definitions from the CCAMP Working Group in the areas that Halabi, author of Internet Routing Architectures cover the GMPLS architecture and concepts. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Understanding GMPLS
Generalized MPLS is a set of architectures and protocols that enables TDM and optical networks to behave more dynamically. GMPLS builds on the MPLS control, which is well known and proven to work, and extends the capabilities of MPLS to control TDM and optical networks, including • Table of Contentsswitches, and physical port switches. TDM switches, wavelength
• Index
Metro Ethernet In the same way that MPLS builds label switched paths (LSPs) between packet switches, GMPLS extends the concept of LSPs to TDM and optical switches. Figure 7-1 illustrates a three-layer BySam Halabi hierarchy where GMPLS LSPs are built between two points in the network over multiple layers. Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 7-1. GMPLS LSPs

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro will emerge as the next area that of growth for the networking industry and will Figurenetworks 7-1 shows how the MPLS LSP concept is used for the IP packet/cell layer can be represent a major shift in how data services are offered to businesses and residential customers. extended to address the TDM and optical layers. On the IP layer, an LSP is formed between The metro hasI. always been challenging for delivering data services because it has routers A and On the TDMalayer, an LSPenvironment is formed between SONET/SDH multiplexers J and N. been built to handle the stringent reliability and availability needs for voice. Carriers will have to On the photonics layer, an LSP is formed between optical switches S and W along the path S-Tgo through fundamental shifts to equip the metro for next-generation data services demanded U-V-W. The establishment of LSPs of course necessitates that TDM and optical switches become by enterprise customers andplane consumers. This is not only a technology shift, but also a shift in the aware of the GMPLS control while still using their own multiplexing and switching operational and business model that will allow the incumbent carriers to transform the metro to techniques. This is one of the powerful advantages of MPLS, because the control and forwarding offer enhanced data services. planes are decoupled. Metro Ethernet Cisco Press looks at the deployment metro data services from a holistic GMPLS has two from applications, both of which can be used inof metro network deployments. First, for view. It describes the current GMPLS metro, can which based on TDM technology, andor discusses the dynamic circuit provisioning, be is used to establish point-to-point multipoint-todrivers and challenges carriers will face in transforming the metro data services. point virtual private optical networks. Second, GMPLS can be used to foraddress protection on the circuit level. In the context of deploying Ethernet services over an optical cloud, GMPLS would extend Metro discusses the adoption of metro Ethernet services and how that has led carriers acrossEthernet L2 Ethernet switches/routers, SONET/SDH multiplexers, and optical cross-connects to the delivery of metro data services. With a changing mix of transport technologies, the book (OXCs) to establish end-to-end circuits. Note that such deployments have not occurred yet, and then examines current and emerging trends, and delves into the role of virtual private networks it is unclear at the moment how fast or slow the adoption of GMPLS will evolve. The next section (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic describes in more detail the need for GMPLS in optical networks. engineering, and MPLS and Generalized MPLS (GMPLS).

Establishing the Need for GMPLS
Anyone who has been in the networking industry for a while would likely raise the issue of whether GMPLS is really needed or is overkill. After all, we have managed so far to build largescale TDM networks with all sorts of methods, and we have seen improvement in tools to • of Contents facilitate the Table operation and management of those networks. To understand the issue of whether • Index GMPLS is necessary, you need to look first at how TDM networks function today and then at how Metro Ethernet they could benefit from GMPLS.
BySam Halabi

The following section describes the provisioning model of today's network deployments, which are more static with centralized management. The problem with this model is that it doesn't Publisher: Cisco Press enable carriers to provide new services that involve the dynamic establishment and restoration Pub Date: October 01, 2003 of TDM and optical circuits while minimizing the operational cost and provisioning times. This is ISBN: 1-58705-096-X the problem that the GMPLS model attempts to address. If GMPLS could solve this problem, the 240 result Pages: would be a better service experience for customers and increased revenue for the carrier. However, adopting GMPLS would also require fundamental changes to the way you administer, manage, and build networks.

The definitive to Enterprise and Carrier Metro Ethernet applications. Static and guide Centralized Provisioning in TDM Networks Currently, TDM and optical networks are provisioned. Provisioning a point-to-point Discover the latest developments in statically metro networking, Ethernet, and MPLS services and circuit takes weeks to accomplish, because it entails lengthy administrative and architectural what they can do for your organization tasks. The majority of today's TDM network management and provisioning models are centralized. Provisioning is done either manually or with automated tools and procedures that Learn from the easy-to-read format that enables networking professionals of all levels to reside in a central network management entity that has knowledge of the whole network and its understand the concepts elements. To handle scalability issues, such as having too many nodes (thousands) to manage, network managers a hierarchical approach in which manageCisco multiple domains Gain from the use experience of industry innovator andthey best-selling Press author, Sam separately and higher layers oversee the whole service operation. The network Halabi, author of management Internet Routing Architectures topology includes topology information about rings and meshed networks. The network Metro networks will emerge as the next of growth for the networking and and will their resources include information about the area network elements, such as fibers, industry ducts, links, represent capacity. a major shift in how data services are offeredis to businesses and residential customers. available Entering such information manually tedious and error-prone, especially in The metro hasrequire always constant been a challenging environment for delivering networks that changes for expansion and upgrades. data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to The provisioning process shifts involves the following: go through fundamental to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to tasks— Request for a circuit involves the paperwork or web-based tools offer Administrative enhanced data services. for a customer such as a large enterprise to fill out and submit as a request for a circuit. request is fulfilled by the network operator. MetroThe Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the Network planning— Thewill network operator has tothe runmetro simulations to find outservices. whether the drivers and challenges carriers face in transforming to address data network has the capacity to absorb the additional circuits and to determine how to optimize network resources. task is done on a set ofand circuits regular intervals. Metrothe Ethernet discusses theThis adoption ofnormally metro Ethernet services how at that has led carriers Network different parts of the network, depending on where these to the deliveryplanning of metrotouches data services. With a changing mix of transport technologies, the circuits book start and end. High-capacity circuits normally put ainto major strain on metropolitan area then examines current and emerging trends, and delves the role of virtual private networks networks that were built for traditional voice services. In some cases, the(VPLS), additiontraffic of one (VPN), virtual private local area networks (VLAN), virtual private LAN services TDM circuit cause the operator to build more metro SONET rings to absorb additional engineering, and might MPLS and Generalized MPLS (GMPLS). capacity; hence, the service could be rejected or delayed until the operator justifies the economics of building more circuits for a particular customer. Installing the physical ports— This is the manual task of installing the WAN ports at the customer premises and installing the connection/circuit between the customer premises and the operator's networks.

Circuit provisioning— This is the task of establishing the circuit end to end, using either management tools or manual configuration. Circuit provisioning is one of the most challenging areas because it requires establishing circuits across multiple components, sometimes from different vendors, with different interfaces and different protocols. Circuit provisioning also involves testing the circuit to see whether it complies with the SLA that was promised to the customer.
• • Table of Contents Billing— As simple as it may sound, a service cannot be deployed until it can be billed for. Index Whether flat billing or usage-based billing is used, the task of defining and accounting for Metro the Ethernet right variables is not simple.
BySam Halabi

Network management— Last but not least is the continuous process of managing the different network elements, keeping the circuits up and running, and restoring the circuits Publisher: Cisco Press in case of network failures.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X

The Effect of a Dynamic Provisioning Model
GMPLS offers a dynamic provisioning model for building optical networks. In this more dynamic and decentralized model, information about the network topology and resources can be exchanged via protocols such as OSPF traffic engineering (OSPF-TE) and IS-IS traffic The definitive guide to Enterprise and Carrier Metro Ethernet applications. engineering (ISIS-TE). The information is available to all nodes in the network, including the Network Management System (NMS), which can act upon it. The dissemination of such information via the routing protocols gives the operator a clearer view and of the network, which Discover the latest developments in metro networking, Ethernet, MPLS services and facilitates provisioning, and operation. what planning, they can do for your organization Figures 7-2 from and 7-3 two scenarios centralization and decentralization. Learn the show easy-to-read formatof that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Figure 7-3. Decentralized, Dynamic Control then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Pages: 240

Figure 7-2. Centralized, Static Control

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Figure 7-2 shows the centralized approach, in which all nodes communicate with the NMS and relay information about topology and resources to a central database. The NMS acts on this Publisher: Cisco Press information for path computation and provisioning.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X In optical networks, the control plane can be exchanged between the different network systems (optical switches, routers, and so on) via in-band or out-of-band communications. The GMPLS Pages: 240 control plane can use multiple communication models:

Over a separate fiber The definitive guide to Enterprise and Carrier Metro Ethernet applications. Over a separate wavelength Over an Ethernet link Discover the latest developments in metro networking, Ethernet, and MPLS services and what they do for your organization Over an IPcan tunnel through a separate management network Learnthe from the easy-to-read format that enables Over overhead bytes of the data-bearing link networking professionals of all levels to understand the concepts A communication over a SONET/SDH data communication channel (DCC), for example, could use Gain from the experience of industry innovator best-selling Press author, Sam the SONET/SDH DCC path D1-D3 or the line D4-D24 and overhead bytes.Cisco For wavelength-division Halabi, author of Internet Routing Architectures multiplexing (WDM) nodes, a separate wavelength could be dedicated as an IP management channel. It is important that the management channel be operational at all times. If, for Metro networks will emergeis as the next areaa of growth failure for thecould networking industry and will example, the management done in-band, network cause the management represent a major shift in how data services are offered to businesses and residential channel to fail. Hence, the nodes and links could become inaccessible and couldn't be customers. restored. The metro has always been a challenging environment for delivering data services because it has been built handle the stringent reliability and needsexchange for voice.topology Carriers will Figure 7-3 to shows the decentralized approach, in availability which the nodes and have to go through fundamental shifts to equip the metro for next-generation data services demanded resource information via different protocols (for example, OSPF-TE) through the IP control plane by enterprise customers and consumers. This is notand only a technology shift, but also a shift in the running in-band or out-of-band. Path computation provisioning can be triggered operational and business model that will allow the incumbent carriers to transform the metro to dynamically or via an NMS station. The NMS station could simply send commands to one of the offer enhanced data services. ingress nodes to initiate a path. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic When applying routing to circuit-switched networks, it is useful to compare and contrast this view. It describes the current metro, which is based on TDM technology, and discusses the situation with the IP packet routing case, which includes the following two scenarios: drivers and challenges carriers will face in transforming the metro to address data services. MetroTopology Ethernet and discusses thediscovery adoption of metro Ethernet services and how that has led carriers resource to the delivery of metro data services. With a changing mix of transport technologies, the book Path computation and emerging provisioning then examines current and trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Topology and Resource Discovery
In the case of routing IP packets, all routes on all nodes must be calculated exactly the same way to avoid loops and "black holes." Conversely, in circuit switching, routes are established per circuit and are fixed for that circuit. To accommodate the optical layer, routing protocols need to

be supplemented with new information, such as available link capacity. Due to the increase in information transferred in the routing protocol, it is important to separate a link's relatively static parameters from those that may be subject to frequent changes. Using a dynamic model to report link capacity in TDM and optical networks can be challenging. You have to find a balance where you are getting accurate reports about specific signals without flooding the network with too much information.
• • Table of Contents Index

Path Computation and Provisioning Metro Ethernet
BySam Halabi

In packet networks, path computation and reachability are very dynamic processes. Routing protocols determine the best path to a destination based on simple metrics such as link Publisher: Cisco Press bandwidth. As described in Chapter 6, "RSVP for Traffic Engineering and Fast Reroute," MPLS Pub Date: October 01,you 2003more control to traffic-engineer the network. For optical networks, path with RSVP-TE gives ISBN: 1-58705-096-X computation and provisioning depend on the following information:
Pages: 240

The available capacity of the network links The switching and termination capabilities of the nodes and interfaces The definitive guide to Enterprise and Carrier Metro Ethernet applications. The link's protection properties When such information is exchanged dynamically via routing protocols, the network always has Discover the developments in metro networking, Ethernet, and to MPLS services and a real-time view oflatest link and node capacity and properties that can be used calculate the most what they can do for your organization suitable path. Learn the easy-to-read formata that enables networking professionals of all levels to With all the from required tasks for deploying service, optimizing the right mix of tasks becomes understand the concepts challenging. No one solution has a positive impact on all variables at the same time. Applying a dynamic provisioning model to the network, for example, would shorten provisioning but would Gain from the planning, experience of industry innovator and best-selling Cisco Press author, Sam also make network service billing, and network management more challenging. After Halabi, author of Internet Routing Architectures all, carriers have always dealt with a static provisioning and TE model, because they have always had total control of the network, its resources, and its behavior. Besides, for legacy Metro networks will emerge as the next area of growth for the networking industry and will SONET equipment that does not have the capability to run GMPLS and dynamic protocols, static represent a major shift in how data services are offered to businesses and residential customers. approaches remain necessary. As such, a combination of static and dynamic, centralized and The metro has always been a challenging environment for delivering data services because it has decentralized approaches would apply to most network designs. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the many metrosteps for next-generation data services demanded The transition to adopting GMPLS will take and will happen faster with some by enterprise customers and consumers. This is not only a technology shift, but also a shift in the providers than others. Adopting this new model will be much easier for alternative providers and operational and business model that will allow the incumbent carriers to transform the metro to greenfield operators than for incumbents, which have well-defined procedures and tools that offer services. have enhanced been useddata for years. The cost justification for adopting GMPLS is not yet as clear as its benefits are. The next section discusses the dynamic provisioning model in more detail. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current which is based on TDM technology, and discusses the To adapt MPLS to control TDMmetro, and optical networks, the following primary issues need to be drivers and challenges carriers will face in transforming the metro to address data services. addressed: Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Addressing then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Signaling engineering, and MPLS and Generalized MPLS (GMPLS). Routing Restoration and survivability The following section begins by looking at the different signaling models that are in use and that

are proposed for optical networks. Chapter 8, "GMPLS Architecture," provides more details about the rest of the topics in the preceding list.

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Signaling Models
Signaling is a critical element in the control plane. It is responsible for establishing paths along packet-switched capable (PSC) and non-PSC networking devices such as routers, TDM crossconnects, and OXCs. PSC networks have no separation between the data and signaling paths; • Table of Contents both data traffic and control traffic are carried over the same channels. In optical networks, • Index control traffic needs to be separated from data traffic. One of the reasons is that OXCs are Metro Ethernetto the data, because they perform light or lambda switching, whereas control traffic transparent needs to be terminated at each intermediary OXC, because it carries the information to manage By Sam Halabi the data flows and information exchange between OXCs. Multiple proposals exist for a signaling infrastructure over optical networks. The most common Pub Date: October 01, 2003 models are the following:
ISBN: 1-58705-096-X Pages: 240 Publisher: Cisco Press

The overlay model The peer model The augmented model The definitive guide to Enterprise and Carrier Metro Ethernet applications.

The Discover Overlay Model the latest developments in metro networking, Ethernet, and MPLS services and
what they can do for your organization In this model, illustrated in Figure 7-4, the internals of the optical infrastructure are totally Learn from the easy-to-read infrastructure. format that enables networking professionals of allas levels transparent to the data-switching The optical infrastructure is treated a to understand the concepts separate intelligent network layer. Data switches at the edges of the optical infrastructure can statically or dynamically provision a path across the optical cloud. This is very similar to the IPGain from the experience of industry innovator and best-selling Cisco Press author, Sam over-ATM model that exists today in carrier backbones. In this model, two independent control Halabi, author of Internet Routing Architectures planes exist: Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in layer— how data services offered businesses and residential customers. Within the packet The controlare plane runsto on the User-to-Network Interface (UNI) The metro has always been a challenging environment for delivering data services because between the data switches at the edge of the optical cloud and the optical switches. it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental to equip the metroplane for next-generation data services demanded Within the opticalshifts network— The control runs on the Network-to-Network by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Interface (NNI) between the optical switches. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.

Figure 7-4. Overlay Model

Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X The overlay model applies in environments with limited or unknown trust that apply strict levels Pages: 240 of policy and authentication and that limit routing information transfer.

The Peer Model
The definitive guide to Enterprise and Carrier Metro Ethernet applications. In the peer model, illustrated in Figure 7-5, the IP/MPLS layers act as peers of the optical transport network, such that a single control plane runs over both the IP/MPLS and optical domains. As far aslatest routing protocols are each edge device is adjacent to the optical Discover the developments inconcerned, metro networking, Ethernet, and MPLS services and switch it is attached to. The label switch routers (LSRs) and OXCs exchange complete what they can do for your organization information. The routers/data switches know the full optical network topology and can compute pathsLearn over it. Forthe data-forwarding purposes, full optical mesh between edge devices is still from easy-to-read format thataenables networking professionals of all levels to needed so that any edge node can communicate with any other edge node. understand the concepts Gain from the experience of Figure industry innovator and best-selling Cisco Press author, Sam 7-5. Peer Model Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic The advantage of MPLS the peer is that, by developing engineering, and andmodel Generalized MPLS (GMPLS). uniform control, it gives the IP layer visibility into the optical layer and supports better IGP scaling if routers are meshed over an operational network. The peer model is much more similar to the use of MPLS than is an IPover-ATM overlay model.

The Augmented Model
The augmented model, illustrated in Figure 7-6, is a hybrid model that falls between the overlay and peer models. In the augmented model, separate control planes for the optical and IP domains are used, but some edge data switches still could have a limited exchange of routing information with border optical switches. This model allows for a transition from the overlay model to the more evolved peer model. One possible scenario in which the augmented model • Table of Contents could be used is where a provider owns the data switches and the border optical switches and • Index relies on a transport service offered by a different provider that owns the core optical switches.
Metro Ethernet BySam Halabi

Figure 7-6. Augmented Model

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Label Switching in a Nonpacket World
MPLS networks consist of LSRs connected via circuits called label switched paths (LSPs). To establish an LSP, a signaling protocol is required. Between two adjacent LSRs, an LSP is locally identified by a short, fixed-length identifier called a label, which is only significant between these • Tablea of Contents two LSRs. When packet enters an MPLS-based packet network, it is classified according to its • Index forwarding equivalency class and, possibly, additional rules, which together determine the LSP Metro alongEthernet which the packet must be sent. For this purpose, the ingress LSR attaches an appropriate label the packet and forwards the packet to the next hop. The label itself is a shim layer By Samto Halabi header, a virtual path identifier/virtual channel identifier (VPI/VCI) for ATM, or a data-link connection identifier (DLCI) for Frame Relay. When a packet reaches a core packet LSR, that LSR Publisher: Cisco Press uses the label as an index into a forwarding table to determine the next hop, and the Pub Date: October 01, 2003 corresponding outgoing label. The LSR then writes the new label into the packet and forwards ISBN: 1-58705-096-X the packet to the next hop. When the packet reaches the egress LSR (or the one node before the Pages: egress LSR 240 for penultimate hop popping), the label is removed and the packet is forwarded using appropriate forwarding, such as normal IP forwarding. So how do these concepts apply to networks that are not packet-oriented, such as TDM- and WDM-based networks? The definitive guide to Enterprise and Carrier Metro Ethernet applications. In TDM networks, the concept of label switching happens at the circuit level or segment level. Switching can happen, for example, at the time-slot level where an input OC3 time slot is crossconnected to an output time slot. in metro networking, Ethernet, and MPLS services and Discover the latestOC3 developments what they can do for your organization For WDM-capable nodes, switching happens at the wavelength level, where an input wavelength is cross-connected toeasy-to-read an output wavelength. As such, SONET/SDH add/drop multiplexers (ADMs) Learn from the format that enables networking professionals of all levels to and OXCs become equivalent to MPLS LSRs, time-slot LSPs and lambda LSPs become equivalent understand the concepts to packet-based LSPs, and the selection of time slots and wavelength becomes equivalent to the selection Gain of from packet thelabels. experience Also,of nonpacket industry innovator LSPs are bidirectional and best-selling in nature, Cisco Press in contrast author, to Sam packet LSPs,Halabi, which are author unidirectional of Internet(this Routing is covered Architectures in more depth in Chapter 8). The following Metro networks section will emerge takes a as closer the next lookarea at label of growth switching for in the TDM-based networking networks industry and and touches will represent upon labelaswitching major shift in in WDM how networks. data services The concepts are offered of label to businesses switching and in both residential TDM and customers. WDM The metro networks are has similar always in been the sense a challenging that with environment TDM networks for GMPLS delivering controls data services circuits and because with WDM it has been built GMPLS controls to handle wavelengths. the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Label Switching in TDM Networks offer enhanced data services. SONET and SDH are two TDM standards are used to multiplex multiple tributary Metro Ethernet from Cisco Press looks at that the deployment of metro data services from signals a holistic over optical links, thus creating a multiplex structure called the SONET/SDH multiplex. Details view. It describes the current metro, which is based on TDM technology, and discusses the about the SONET/SDH structure are covered in Appendix A, "SONET/SDH Basic Framing and drivers and challenges carriers will face in transforming the metro to address data services. Concatenation." Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers If to the data GMPLS controlWith plane to control mix the of SONET/SDH multiplex, you must to you the choose delivery ofuse metro services. a changing transport technologies, the book decide which ofcurrent the different components of the SONET/SDH that can private be switched need then examines and emerging trends, and delves into multiplex the role of virtual networks to be controlled using local GMPLS. As described in Appendix A, the SONET/SDH frame format (VPN), virtual private area networks (VLAN), virtual private LAN services (VPLS), traffic consists of overhead bytes, payload, and a pointer to the payload. Essentially, every engineering, and MPLS and a Generalized MPLS (GMPLS). SONET/SDH element that is referenced by a pointer can be switched. These component signals in the SONET case are the synchronous transport signal (STS), Synchronous Payload Envelopes (SPEs), and virtual tributaries (VTs), such as STS-1, VT-6, VT-3, VT-2, and VT-1.5. For SDH, the elements that can be switched are the VC-4, VC-3, VC-2, VC-12, and VC-11. When concatenation is used in the case of SONET or SDH, the new structure can also be

referenced and switched using GMPLS. As explained in Chapter 2, "Metro Technologies," concatenation—standard or virtual—allows multiple tributaries or STS/STM to be bonded to create a bigger pipe. GMPLS can be applied on the concatenated pipe. The following sections discuss in more detail the concepts of label switching in a TDM network, including the following:
• •
BySam Halabi

Table Contents Signaling in of a TDM network Index

Metro SONET/SDH Ethernet

LSRs and LSPs

The mechanics and function of a TDM label

Publisher: Cisco Press Pub Date: October 01, 2003 Signaling in a TDM Network ISBN: 1-58705-096-X

To support signaling in the TDM network, several modifications need to be made to MPLS. First, the traditional MPLS label needs to be modified to provide better binding between the label itself and the circuit it represents on a particular interface. Second, an LSP hierarchy needs to be introduced so that LSPs that represent signals can be tunneled inside other LSPs. Third, the capabilities of the label distribution protocols need to be extended so that they can distribute the The definitive guide to Enterprise and Carrier Metro Ethernet applications. information that is necessary to switch the signals along the path. A high-level description of the signaling modifications is covered in the next section, and a more detailed description is available in Chapter 8. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

Pages: 240

SONET/SDH LSRs and LSPs format that enables networking professionals of all levels to Learn from the easy-to-read
understand the concepts GMPLS defines a SONET/SDH terminal multiplexer, an ADM, and a SONET cross-connect as Gain from theA experience of industry innovator and best-selling Cisco Press author, SONET/SDH LSRs. path or circuit between two SONET/SDH LSRs becomes an LSP. A Sam Halabi, author of Internet Routing Architectures SONET/SDH LSP is a logical connection between the point at which a tributary signal (client layer) is adapted to its SPE for SONET or to its virtual container for SDH, and the point at which Metro networks will its emerge as the next area of Figure growth7-7 for shows the networking industry and it is extracted from SPE or virtual container. a SONET/SDH LSP. In will this represent a major shift in how data services are offered to businesses and residential customers. example, an STS-1 LSP is formed between path terminal equipment—PTE1 and PTE2—across The metro has always been a challenging environment data services because it has line terminal equipment—LTE1 and LTE2. The LTEs are for thedelivering SONET/SDH network elements that been built to handle the stringent reliability and availability needs for voice. Carriers will have to originate or terminate the line signal. The PTEs are the SONET/SDH network elements that go through fundamental shifts to equip the metro for next-generation data services demanded multiplex/demultiplex the payload. A PTE, for example, would take multiple DS1s to form an by enterprise customers and consumers. This is not only a technology shift, but also a shift in the STS-1 payload. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.

Figure 7-7. GMPLS LSP Across SONET Equipment

Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). To establish a SONET/SDH LSP, a signaling protocol is required to configure the input interface, switch fabric, and output interface of each SONET/SDH LSR along the path. A SONET/SDH LSP can be point-to-point or point-to-multipoint, but not multipoint-to-point, because no merging is possible with SONET/SDH signals. To facilitate the signaling and setup of SONET/SDH circuits, a

SONET/SDH LSR must identify each possible signal individually per interface, because each signal corresponds to a potential LSP that can be established through the SONET/SDH LSR. GMPLS switching does not apply to all possible SONET/SDH signals—only to those signals that can be referenced by a SONET/SDH pointer, such as the STS SPEs and VTs for SONET and the VC-X s for SDH. The next section addresses the mechanics and functions of a GMPLS label in the context of TDM networks.
• •
Metro Ethernet BySam Halabi

Table of Contents Index

The Mechanics and Function of a TDM Label
You have already seen label switching adopted with an asynchronous technology such as IP Publisher: Cisco Press where a label attaches to an IP packet and helps put that packet on the right LSP in the direction Pub Date: October 01, of its destination. For2003 SONET/SDH, which are synchronous technologies that define a ISBN: 1-58705-096-X multiplexing structure, GMPLS switching does not apply to individual SONET/SDH frames. GMPLS Pages: switching 240 applies to signals, which are continuous sequences of time slots that appear in a SONET/SDH frame. GMPLS can switch SONET/SDH signals. As such, a SONET/SDH label needs to indicate the signals that can be switched, such as the STS SPE, VTs, and virtual containers. Figure 7-8 compares label switching applied to TDM and traditional label switching in the packet world. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Figure 7-8. SONET/SDH Label Switching
Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. As youEthernet can see,from with Cisco a packet LSR, theat labels are identified a certain forwarding equivalency Metro Press looks the deployment of for metro data services from a holistic class are usedthe to label-switch the packet its destination. The labels themselves are carried view. and It describes current metro, which is to based on TDM technology, and discusses the inside the IP packets for the LSR to face perform the label-switching function. In the case of a drivers and challenges carriers will in transforming the metro to address data services. SONET/SDH LSR, the GMPLS control plane needs to map labels for the signals that need to be Metro Ethernet discusses the adoption of metro services and how I1 that has led carriers switched on each interface. In this example, theEthernet STS-1 signal on interface is mapped to label to the delivery of metro data services. With a changing mix of transport technologies, the book 10 and is cross-connected to the STS-1 signal on interface I3, which is mapped to label 30. The then examines current and emerging trends, and delves into the role of virtual private networks VT 1.5 signal on interface I2 is mapped to label 20 and is cross-connected to the VT 1.5 signal (VPN), virtual private area networks (VLAN), private LAN services traffic on interface I4, which local is mapped to label 40. Note virtual that the SONET/SDH frames(VPLS), themselves do engineering, and MPLS and Generalized MPLS (GMPLS). not carry any label; the mapping is just an indication by the GMPLS plane to allow the SONET/SDH node to perform the required switching function of the appropriate signals. A SONET/SDH LSR has to identify each possible signal individually per interface to fulfill the GMPLS operations. To stay transparent, the LSR obviously should not touch the SONET/SDH overheads; this is why an explicit label is not encoded in the SONET/SDH overheads. Rather, a

label is associated with each individual signal and is locally unique for each signal at each interface. Because the GMPLS label is not coded in the signal itself, a mechanism needs to be established to allow the association of a label with SONET/SDH signals. The GMPLS label is defined in a way that enables it to give information about the SONET/SDH multiplex, such as information about the particular signal and its type and position in the multiplex.
• • Table of Contents Index

Label Switching in WDM Networks Metro Ethernet
BySam Halabi

WDM is a technology that allows multiple optical signals operating at different wavelengths to be multiplexed onto a single fiber so that they can be transported in parallel through the fiber. Publisher: Cisco Press OXCs in turn cross-connect the different wavelengths, in essence creating an optical path from Pub Date: October 01, 2003 source to destination. The optical path itself can carry different types of traffic, such as ISBN: 1-58705-096-X SONET/SDH, Ethernet, ATM, and so on. OXCs can be all optical, cross-connecting the Pages: 240 wavelengths in the optical domain, or they can have optical-to-electrical-to-optical conversion, which allows for wavelength conversion mechanisms. In the GMPLS context, OXCs would run the GMPLS control plane and would become comparable to LSRs. Lambda LSPs are considered similar to packet-based LSPs, and the selection of wavelengths and OXC ports is considered similar to label selection. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Figure 7-9 compares the concept of MPLS switching in a WDM network in the same way that Figure 7-8 did for the TDM network. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for Figure your organization 7-9. WDM Label Switching Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers andshown challenges carriers will facethe in transforming the metro to address data As already in the TDM example, GMPLS labels are not carried inside the services. actual packet. In the case of an OXC LSR, the GMPLS control plane needs to map labels for the lambdas that Metro Ethernet discusses the interface. adoption of Ethernet services how that has led carriers need to be switched on each In metro this example, label 1 onand interface I1 is mapped to to the delivery of metro data services. With a changing mix of transport technologies, the book lambda 1 and cross-connected to lambda 1 on I3, which is mapped to label 1. Again, because then examines current and emerging trends, andadelves into the role to of be virtual private to networks the GMPLS label is not coded in the wavelength, mechanism needs established (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic associate lambdas with labels. This is discussed in Chapter 8. engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
As discussed in this chapter, GMPLS is necessary to establish a dynamic way to provision optical networks. You have seen the benefits and drawbacks of both the static centralized and dynamic decentralized provisioning models. The chapter also discussed the different signaling models, • Table of Contents such as the overlay, peer, and augmented models. These resemble how IP packet-based • networks areIndex deployed today over ATM or Frame Relay circuit-based networks. You have also Metro Ethernet seen how GMPLS uses labels to cross-connect the circuits for TDM and WDM networks. Although the concept By Sam Halabi of labels was adopted, the use of these labels is quite different from the traditional use of labels in data forwarding. The next chapter goes into more detail about the extensions to routing and signaling that were Pub Date: October 01, 2003 added to the traditional MPLS control plane to accommodate optical networks.
ISBN: 1-58705-096-X Pages: 240 Publisher: Cisco Press

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Chapter 8. GMPLS Architecture
This chapter covers the following topics:
• •

GMPLS Interfaces
Index

Table of Contents

Metro Modification Ethernet BySam Halabi

of Routing and Signaling

Inclusion of Technology-Specific Parameters
Publisher: Cisco Press Pub Date: October 01, 2003

Link Management Protocol
ISBN: 1-58705-096-X GMPLS Protection and Restoration Mechanisms Pages: 240

Summary of Differences Between MPLS and GMPLS Optical networks present some added challenges that do not normally exist in packet-switched networks (PSNs) and hence cannot be fully addressed by the traditional MPLS schemes. Here are a few examples of these challenges: The definitive guide to Enterprise and Carrier Metro Ethernet applications. Optical/TDM bandwidth allocation is done in discrete amounts, whereas in PSNs, bandwidth Discover the latest developments inspectrum. metro networking, Ethernet, and MPLS services and can be allocated from a continuous what they can do for your organization The number of links in an optical network can be orders of magnitude larger than in a Learn fromnetwork, the easy-to-read format thatexplosion enables networking professionals all levels to traditional due to the possible in the number of parallel of fibers deployed understand the concepts and the number of lambdas on each fiber. This in turn raises the issues of IP address assignment for optical links and the manageability of connecting ports on different network Gain from the experience of industry innovator and best-selling Cisco Press author, Sam elements. If a fiber has 32 wavelengths, for example, between points A and B, and if each Halabi, author of Internet Routing Architectures wavelength is treated as a separate link with its own addressing, the one fiber will create 32 different networks that need to area be addressed and Metro networks will emerge as the next of growth for managed. the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Fast fault detection and isolation have always been advantages that optical networks have The metro has always been a challenging environment for delivering data services because it has over PSNs. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts the metro for next-generation data services demanded The fact that user data in to anequip optical network is transparently switched necessitates the by enterprise customers and consumers. This is not only a technology shift, but also a shift in the decoupling of user data from control plane information. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Generalized MPLS (GMPLS) attempts to address these challenges by building on MPLS and extending its control parameters to handle the scalability and manageability aspects of optical Metro Ethernet from Cisco Press the looks at the deployment of metro data services from holistic networks. This chapter explains characteristics of the GMPLS architecture, such asa the view. It describes the current metro, which is based on TDM technology, and discusses the extensions to routing and signaling and the addition of technology parameters, that GMPLS adds drivers and challenges carriers will face in transforming the metro to address data services. to MPLS to be able to control optical networks. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

GMPLS Interfaces
The GMPLS architecture extends MPLS to include five different types of interfaces used on label switch routers:
• • Table of Contents

Packet-switch capable (PSC) interfaces— Interfaces that can recognize packet Index and forward data based on packet headers. This is typical of interfaces on Metro boundaries Ethernet routers and L3 Ethernet switches. BySam Halabi
Publisher: Press frame Cisco boundaries

Layer 2–switch capable (L2SC) interfaces— Interfaces that can recognize L2 cell or and forward data based on L2 headers. This is typical of interfaces on Pub Date: October 01,Frame 2003 ATM switches, Relay switches, and L2 Ethernet switches.
ISBN: 1-58705-096-X

Time-division multiplexing (TDM) interfaces— Interfaces that can recognize time slots Pages: 240 and forward data based on the data's time slot in a repeating cycle. This is typical of interfaces on digital cross-connects (DACSs), SONET add/drop multiplexers (ADMs), and SONET cross-connects. Such interfaces are referred to as TDM capable. Lambda-switch capable (LSC) interfaces— Interfaces that can forward data based on The definitive guide to Enterprise and received Carrier Metro Ethernet applications. the lambda (wavelength) it was on. This is typical of optical cross-connects (OXCs) that switch traffic on the wavelength level. Discover the latest developments in metro networking, Ethernet, and MPLS services and Fiber-switch capable (FSC) interfaces— Interfaces that can forward data based on the what they can do for your organization position of the data in real-world physical spaces. This is typical of OXCs that switch traffic on the fiber or multiple-fiber level. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Modification of Routing and Signaling
The development of GMPLS requires the modification of current routing and signaling protocols. The adoption of a common, standardized control plane for managing packet/cell switches and optical switches is extremely important to the networking industry. This introduces a unified • Table of Contents method for achieving fast provisioning, restoration, routing, monitoring, and managing data• switched andIndex optical-switched networks while maintaining interoperability between multiple Metro Ethernet vendors. The MPLS control plane is being extended from controlling data switches to a more generic role of controlling any type of switching, including optical switching—hence the term By Sam Halabi Generalized MPLS. To help MPLS span switches that are not packet-oriented, GMPLS introduces some modifications Pub Date: October 01, 2003 to MPLS in the areas of routing and signaling. The modifications take place in the following areas: ISBN: 1-58705-096-X
Pages: 240 Publisher: Cisco Press

Enhancements to routing protocols Enhancements to signaling protocols The guide to discuss Enterprise and Carrier Metro Ethernet applications. The definitive following sections routing and signaling enhancements. Discover the latest developments in metro networking, Ethernet, and MPLS services and

Enhancements to Routing what they can do for your organization

Learn from theinto easy-to-read format networks that enables networking of all levelsnodes to Introducing routing TDM and optical does not mean professionals turning TDM and optical understand the concepts into IP routers, but rather using the benefits of routing protocols as far as relaying paths and resource information to better use network resources. In optical and TDM networks, this Gain from the experience of industry innovator and best-selling Cisco Press author, Sam information includes the following: Halabi, author of Internet Routing Architectures Metro networks willcapacity emerge of asthe thenetwork next area of growth for the networking industry and will The available links represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has The switching and termination capabilities of the nodes and interfaces been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded The link's protection properties by enterprise customers and consumers. This is not only a technology shift, but also a shift in the This information is carried insidethat routing protocols such as Open Shortest Path Firstthe for metro Trafficto operational and business model will allow the incumbent carriers to transform Engineering (OSPF-TE) and IS-IS Traffic Engineering (IS-IS–TE). GMPLS introduces extensions offer enhanced data services. to OSPF-TE and IS-IS–TE to allow these protocols to tailor to the specific information required by Metro networks. Ethernet from Cisco Press looks at the deployment metro from protocols a holistic these OSPF-TE and IS-IS–TE are extensions of of the OSPFdata and services IS-IS routing view. It describes current metro, which is about based available on TDM technology, and discusses that allow them tothe carry network information network resources. This the drivers and challenges carriers will face transforming the metro to address data services. information is used by protocols such asin RSVP-TE to engineer the traffic in the network. Metro Ethernet discusses the adoption of metro Ethernet how that a has led carriers An MPLS TE link is considered to be like any regular link, services meaningand a link where routing to the delivery of metro data services. With a changing mix of transport technologies, the book protocol adjacency is brought up via protocols such as OSPF. The link's Shortest Path First (SPF) then examines current and emerging trends, and delves into the role of virtual private networks properties and the TE properties are calculated and advertised. For GMPLS to accommodate (VPN), virtual private local area networks virtual private LAN services (VPLS), traffic optical networks, a few variations need to (VLAN), be introduced: engineering, and MPLS and Generalized MPLS (GMPLS). Nonpacket links can be brought up without establishing a routing adjacency. A label switched path (LSP) can be advertised as a point-to-point TE link, and the advertised TE link need no longer be between two OSPF/IS-IS direct neighbors.

A number of links can be advertised as a single TE link, and there is no one-to-one association between routing adjacencies and a TE link. A GMPLS TE link has special TE properties that can be configured or obtained via a routing protocol. An example of TE properties would be the bandwidth accounting for the TE link, including the unreserved bandwidth, the maximum reservable bandwidth, and the maximum LSP bandwidth. Other properties include protection and restoration characteristics.
• Table of Contents IS-IS–TE and OSPF-TE explain how to associate TE properties to regular (packet-switched) links. • Index GMPLS extends the set of TE properties and also explains how to associate TE properties with Metro Ethernet links that are not packet-switched, such as links between OXCs.
BySam Halabi

Figure 8-1 shows a TE link.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 8-1. GMPLS TE Link

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain in from the 8-1, experience of industry innovator and best-selling Cisco Press Sam As shown Figure a GMPLS TE link extends beyond two adjacent nodes andauthor, can include Halabi, author of Internet Routing Architectures multiple parallel component links. The end nodes of the link do not have to be part of a routing adjacency. In the context of MPLS, the link is between two adjacent nodes A and B and forms a Metro networks will emerge as the next area of growth for the networking industry and will routing adjacency using a routing protocol, say OSPF. In the GMPLS context, the link traverses represent a major shift in how data services are offered to businesses and residential customers. multiple nodes and the two label switch routers (LSRs) B and C. A and F do not have to establish The metro has always been a challenging environment for delivering data services because it has a routing adjacency. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through shifts to equip the metro for next-generation data services demanded The GMPLS fundamental enhancements to routing include the following: by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer LSP enhanced data services. hierarchy—routing MetroUnnumbered Ethernet from Cisco Press looks at the deployment of metro data services from a holistic links view. It describes the current metro, which is based on TDM technology, and discusses the Link bundling drivers and challenges carriers will face in transforming the metro to address data services. protection types MetroLink Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Shared link groupand information then examines current emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Interface switching capability descriptor engineering, and MPLS and Generalized MPLS (GMPLS). The next sections examine each of these enhancements to routing introduced by GMPLS.

LSP Hierarchy—Routing

The difference between the traditional fiber networks and WDM networks is that WDM introduces a significant increase in the number of paths between two endpoints, mainly because it introduces hundreds of wavelengths on each fiber. Couple that with the possibility of tens and hundreds of fibers between two optical switches, and the number of paths could become challenging to traditional routing protocols if every path (LSP) is considered a separate link in interior routing protocols such as OSPF and IS-IS. LSP hierarchy canof address • Table Contentsthis issue by allowing LSPs to be aggregated inside other LSPs. There is a natural order for this aggregation that is based on the multiplexing capability of the LSP • Index types. With GMPLS, LSPs start and end on devices of the same kind, such as routers, TDM Metro Ethernet switches, WDM switches, and fiber switches. An LSP that starts and ends on a packet-switchBySam Halabi capable (PSC) interface can be nested with other LSPs into an LSP of type TDM that starts and ends on a TDM interface, which can be nested in LSC-LSPs that start and end on an LSC Publisher: Cisco Press interface, which could be nested in FSC-LSPs that start and end on FSC interfaces. This is Pub Date:in October 01,8-2. 2003 illustrated Figure
ISBN: 1-58705-096-X Pages: 240

Figure 8-2. GMPLS LSP Hierarchy

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam of Internet Routing WhenHalabi, an LSRauthor establishes an LSP, it can Architectures advertise the LSP in its instance of routing protocol (OSPF or IS-IS) as a TE link. This link is called a forwarding adjacency (FA). The LSP itself is Metro networks will emerge as the next area of growth referred to as the forwarding adjacency LSP, or FA-LSP.for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always a challenging environment for delivering data services it has IS-IS/OSPF floods the been information about FAs just as it floods the information aboutbecause any other been built to handle the stringent reliability and availability needs for voice. Carriers will have to links. As a result of this flooding, an LSR has in its TE link-state database information about not go through fundamental shifts to equip the metro for next-generation data services demanded just basic TE links, but FAs as well. Figure 8-2 shows how GMPLS FA-LSP can be carried within by enterprise customers and FA-LSPs consumers. This is not only a technology shift, FA-TDMs, but also a and shift in the other FA-LSPs. The different introduced in this figure are FA-LSCs, FAoperational and business model that will allow the incumbent carriers to transform the metro to PSCs. offer enhanced data services. Figure 8-2 shows the following: Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers 1. FA-LSCs and challenges are formed carriers by nodes will face that in sittransforming at the boundary the metro of a lambda to address clouddata and services. a fiber cloud. The FA-LSCs get advertised in the routing protocols and are available to be used as any Metroother Ethernet discusses the adoption of metro Ethernet services and how that has led carriers TE links. to the delivery of metro data services. With a changing mix of transport technologies, the book then 2. examines Nodes that current sit at the and boundary emerging of trends, a TDM and cloud delves and a into lambda the role cloud of virtual form FA-TDMs. private networks The FA(VPN), TDMs virtual getprivate advertised localas area TE networks links. (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). 3. Nodes that sit at the boundary of a PSC/L2SC and TDM cloud form FA-PSCs or FA-L2SCs that get advertised as TE links. 4. Low-order packet LSPs can be combined and tunneled inside higher-order FA-PSCs. In the same manner, low-order FA-PSCs can be combined and tunneled inside higher-order FA-

5.

4. TDMs, which can be combined and tunneled inside higher-order FA-LSCs. 5. FAs (links) are either numbered or unnumbered and can be bundled according to the GMPLS bundling procedures.

Unnumbered Links
• Table of Contents

As in an IP network, the nodes in an optical network have to be addressed and referenced. • Index Addressing these nodes helps identify not only the nodes but also the components—that is, the Metro Ethernet links of each of these nodes. Addressing allows signaling protocols such as RSVP to establish BySam Halabi optical paths across the OXCs.
Publisher: Cisco Press In normal routing, each link in the network can be identified via its own subnet. This has proven Pub Date: October even 01, 2003 to be challenging in packet networks because it requires the assignment and management of many ISBN: small 1-58705-096-X subnets. In optical networks, in which the number of links can increase dramatically, IP address assignment proves much more challenging because a fiber can carry Pages: 240 hundreds of wavelengths. Thus, the concept of unnumbered links should be quite useful.

Anunnumbered link is a point-to-point link that is referenced using a link identifier. The link identifier is a unique, nonzero, 32-bit local identifier. The identifier for the local node is called thelocal link identifier, while the link identifier for the remote node is called the remote link The definitive guide to Enterprise and is Carrier Metro a Ethernet applications. identifier. If the remote link identifier not known, 0 identifier is used instead. A network node can be addressed via a router ID (normally the highest or lowest IP address on Discover the latest developments in metro networking, Ethernet, and MPLS services and that node). The links on that node can then be identified locally via the tuple (router ID, link what they can do for your organization number). Exchanging the identifiers may be accomplished by multiple methods, including configuration, LMP, IS-IS/OSPF, andenables so on. networking professionals of all levels to Learn from theRSVP-TE, easy-to-read format that understand the concepts Figure 8-3 illustrates the concept of unnumbered links. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Figure 8-3. Unnumbered Links Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 8-3 shows how node A identifies each link with a tuple formed with its router ID RID-A and the local link identifier.

Current signaling used by MPLS TE doesn't provide support for unnumbered links because the current signaling doesn't provide a way to indicate an unnumbered link in its EXPLICIT_ROUTE object (ERO) and RECORD_ROUTE object (RRO). Extensions to RSVP-TE define an optional object called LSP_TUNNEL_INTERFACE_ID that could be used in RSVP PATH or Reservation (RESV) messages. The LSP_TUNNEL_INTERFACE_ID object is an LSR router ID and a 32-bit interface ID tuple. Also, subobjects of the ERO and RRO are defined for the support of unnumbered links.
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BySam Halabi

Table of Contents Index

Link Bundling Metro Ethernet
Link bundling allows multiple TE links to be bundled into one bigger TE link. The subset links are called component links, and the group of links is called a bundled link. Publisher: Cisco Press
Date: October 01, 2003 On Pub a bundled link, a combination of <(bundled) link identifier, component link identifier, label> ISBN: is sufficient 1-58705-096-X to unambiguously identify the appropriate resources used by an LSP. Pages: 240

Link bundling improves routing by reducing the number of links and associated attributes that are flooded into routing protocols such as OSPF and IS-IS. Link bundling allows multiple parallel links of similar characteristics to be aggregated and flooded as a bundled link. Figure 8-4 shows this concept. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Figure 8-4. Link Bundling
Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet links fromin Cisco Pressmust: looks at the deployment of metro data services from a holistic All component a bundle view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Begin and end on the same pair of LSRs Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Have the same linkdata type, such as With point-to-point or mix multiaccess to the delivery of metro services. a changing of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks Have the private same TE metric (VPN), virtual local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Have the same set of resource classes at each end of the links A bundled link is considered alive if one of its component links is alive. Determining the liveliness of the component links can be done via routing protocols, LMP, or L1 or L2 information. Once a bundled link is considered alive, the information about the bundled link is flooded as a TE link.

WARNING
The benefits of link bundling in reducing the number of flooded links come at the expense of loss of information. Link bundling involves the aggregation of the component links, and in the process of summarizing the attributes of several links into • Table of Contents a bundled link, information is lost. Remember that the information that is flooded in • Index the routing protocols is information about the bundled link itself and not information Metroabout Ethernet the component links. As an example, when multiple parallel SONET links are summarized, information about the total reservable bandwidth of the component links BySam Halabi is advertised, but information about the bandwidth and time slots of each link is lost.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X While the link-state protocols carry a single bundled link, signaling requires that individual component Pages: 240 links be identified. Because the ERO does not carry information about the component links, the component link selection becomes a local matter between the LSR bundle neighbors. LMP offers a way to identify individual component links. (LMP is described later in the chapter, in the section "Link Management Protocol.")

The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Link Protection Types

Discover the latest developments metro networking, Ethernet, and services and GMPLS introduces the concept of a link in protection type, which indicates theMPLS protection what they can do for your organization capabilities that exist for a link. Path computation algorithms use this information to establish links with the appropriate protection characteristics. This information is organized in a hierarchy Learn from the easy-to-read format that enables networking professionals of all levels to where typically the minimum acceptable protection is specified at path instantiation and a path understand the concepts selection technique is used to find a path that satisfies at least the minimum acceptable protection. The different link protection types are as follows: Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Extra Traffic— This type of link protects another link or links. In case of failure of the Metro networks will emerge as the next area of growth for the networking industry and will protected links, all LSPs on this link are lost. represent a major shift in how data services are offered to businesses and residential customers. The metro has alwaysThis been a challenging environment for delivering data services because it has Unprotected— type of link is simply not protected by any other link. If the been unprotected built to handle the stringent reliability and availability needs for voice. Carriers will have to link fails, all LSPs on the link are lost. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers consumers. This is one not or only a technology shift, also a shift in the Shared— This typeand of link is protected by more disjoint links of but type Extra Traffic. operational and business model that will allow the incumbent carriers to transform the metro to offer Dedicated enhanced data services. 1:1— This type of link is protected by a disjoint link of type Extra Traffic. MetroDedicated Ethernet from Cisco Press looks at is the deployment metro link data services from a holistic 1+1— This type of link protected by a of disjoint of type Extra Traffic. view.However, It describes current link metro, which is basedin on TDM technology, and discusses the is thethe protecting is not advertised the link-state database and therefore drivers and challenges carriers will face in transforming the metro to address data services. not used by any routing LSPs. MetroEnhanced— Ethernet discusses the adoption of metro Ethernet services and that how is that hasreliable led carriers This type of link indicates that a protection scheme more than to the delivery of metro data services. With a changing mix of transport technologies, the book Dedicated 1+1 should be used—for example, four-fiber BLSR. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), 8-5 Figure virtual shows private the different local area protection networks types. (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Figure 8-5. Link Protection Types

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and Link A-B-D is protected by your link A-C-D. Link A-C-D is of type Extra Shared. The following what they can do for organization protection scenarios can occur: Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Link A-B-D is 1+1 protected— Link A-C-D protects link A-B-D. Link A-C-D is not advertised andexperience hence does not carry any LSPs unless link A-B-D Cisco fails. Press author, Sam Gain from the of industry innovator and best-selling Halabi, author of Internet Routing Architectures Link A-B-D is 1:1 protected— Link A-C-D protects link A-B-D. Link A-C-D is advertised and can carry but it the gets preempted to protect if linkindustry A-B-D fails. Metro networks will LSPs, emerge as next area of growth for link the A-B-D networking and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Shared Risk Link Group Information been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and a consumers. not only a technology shift, but also a shift in the A set of links may constitute shared riskThis link is group (SRLG) if they share a resource whose operational and business model that will allow the incumbent carriers to transform the metro to failure may affect all links in the set. Multiple fibers in the same conduit, for example, could offer enhanced data services. constitute an SRLG because a conduit cut may affect all the fibers. The same applies to multiple lambdas in a fiber that can all be affected if a fiber cut occurs. The SRLG is an optional 32-bit Metro Ethernet from Cisco Press looks at the deployment metroto data services fromThe a holistic number that is unique within an IGP domain. A link mightof belong multiple SRLGs. SRLG view. It describes the current metro, which is based on TDM technology, and discusses the of an LSP is the union of the SRLGs of the links in the LSP. The SRLG information is used to make drivers and challenges carriers face in transforming the metro to address services. sure that diversely routed LSPs will do not have a common SRLG—that is, they dodata not share the same risks of failure. Figure 8-6 illustrates the concept of an SRLG. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Figure 8-6. Shared Riskinto Link then examines current and emerging trends, and delves theGroup role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure 8-6 shows that all links that pass through conduit 1 share the same SRLG. The same is true for all links that pass through conduit 2. If the SRLG option is used, two LSPs that need to be diversely routed between node A and node D cannot both pass through conduit 1 or conduit 2, because they would have the same SRLGs in common. The definitive guide to Enterprise and Carrier Metro Ethernet applications.

Interface Discover Switching the latest Capability developments Descriptor in metro networking, Ethernet, and MPLS services and
what they can do for your organization In the context of GMPLS, a link is connected to a node via an interface. An interface on the same from the easy-to-read thatmultiple enables switching networking professionals all levels to node Learn and on either side of the linkformat may have capabilities. Theof interface understand the concepts switching capability descriptor is used to handle interfaces that support multiple switching capabilities, for interfaces that have Max LSP Bandwidth values that differ by priority level (P), Gain from the experience of industry innovator and best-selling Cisco Press author, Sam and for interfaces that support discrete bandwidth. A fiber interface, for example, that is Halabi, author of Internet Routing Architectures connected to a node can carry multiple lambdas, and each lambda can be terminated. If the lambda is carrying can be performed. If the lambda is carrying a TDM Metro networks willpackets, emerge packet-switching as the next area of growth for the networking industry and will circuit, the TDM circuit is switched. If the lambda is not terminated at the node, the lambda itself represent a major shift in how data services are offered to businesses and residential customers. can be lambda switched. To support such interfaces, a link-state advertisement would carry ahas list The metro has always been a challenging environment for delivering data services because it of interface switching descriptors. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded You saw in the "GMPLS Interfaces" section that GMPLS defines five types of interfaces: PSC, by enterprise customers and consumers. This is not only a technology shift, but also a shift in the L2SC, TDM, LSC, and FSC. The following list describes the interface descriptors associated with operational and business model that will allow the incumbent carriers to transform the metro to these types of interfaces: offer enhanced data services. MetroFor Ethernet from Cisco Press looks at the metro4 data services from a a hierarchy holistic the PSC interfaces, various levels of deployment PSC from 1 of through exist to establish view.of It LSPs describes the current metro, which is based on TDM technology, and discusses the tunneled within LSPs, with PSC 1 being the highest order. drivers and challenges carriers will face in transforming the metro to address data services. For interfaces of type PSC1 through 4, TDM, and LSC, the interface descriptor carries Metroadditional Ethernet discusses the adoption of metro Ethernet services and how that has led carriers information in the following manner: to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (Max) (VPLS), traffic - For PSC interfaces, the additional information includes Maximum LSP engineering, and MPLS and Generalized MPLS (GMPLS). Bandwidth, Minimum (Min) LSP Bandwidth, and interface MTU. - For TDM-capable interfaces, the additional information includes Maximum LSP Bandwidth, information on whether the interface supports standard or arbitrary SONET/SDH, and Minimum LSP Bandwidth.

- For LSC interfaces, the additional information includes Reservable Bandwidth per priority, which specifies the bandwidth of an LSP that can be supported by the interface at a given priority number.

Determining the Link Capability
• Table of Contents The link capability is determined based on the tuple <interface switching capability, label>. • Index Carrying label information on a given TE link depends on the interface switching capability at Metro Ethernet both ends of the link and is determined as follows:
BySam Halabi

[PSC, PSC]— The label is carried in the "shim" header (RFC 3032, MPLS Label Stack
Publisher: Cisco Encoding ).Press Pub Date: October 01, 2003

[TDM, TDM]— The label represents a TDM time slot. ISBN: 1-58705-096-X [LSC, LSC]— The label represents a port on an OXC. [PSC, TDM]— The label represents a TDM time slot. [TDM, LSC]— The label represents a port. The definitive guide to Enterprise and Carrier Metro Ethernet applications.
Pages: 240

Interface Switching Capability Descriptor Examples Discover the latest developments in metro networking, Ethernet, and MPLS services and
what they can do for your organization The following are examples of interface switching capability descriptors. Learn from the easy-to-read format that enables networking professionals of all levels to Fast Ethernet 100-Mbps Ethernet packet interface on an LSR: understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Interface switching capability descriptor: Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will - Interface Switching Capability = PSC-1 represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging - Encoding = Ethernet 802.3 environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip theMbps metro for next-generation data services Max LSP Bandwidth[P] = 100 for all P (where P indicates the LSP demanded priority by enterprise customers and consumers. This is not only a technology shift, but also a shift in the level; a priority of 7, for example, gives the LSP high priority) operational and business model that will allow the incumbent carriers to transform the metro to offerfollowing enhanced The isdata how services. the interface descriptor is represented for an OC-192 SONET interface on a digital cross-connect with Standard SONET. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current which based on TDM technology, and discusses the STSAssuming that it is possible tometro, establish the is following connections, VT-1.5, STS-1, STS-3c, drivers and challenges carriers will face in transforming thedescriptor metro to address data services. 12c, STS-48c, STS-192c, the interface switching capability of that interface can be advertised as follows: Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines Interface Switching current and Capability emerging = trends, TDM [Standard and delves SONET] into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Encoding = SONET ANSI T1.105 MPLS (GMPLS). engineering, and MPLS and Generalized Min LSP Bandwidth = VT1.5 Max LSP Bandwidth[p] = STS192 for all p (where p refers to LSP priority)

Enhancements to Signaling
GMPLS enhances the traditional MPLS control plane to support additional different classes of interfaces, such as TDM, LSC, and FSC. The support of these interfaces requires some changes to signaling, such as the following: LSP hierarchy—signaling Table of Contents
Index

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Metro Enhancements Ethernet BySam Halabi

to labels

Bandwidth encoding

Publisher: Bidirectional Cisco Press LSPs Pub Date: October 01, 2003

Notification of label error ISBN: 1-58705-096-X
Pages: 240 Explicit label control

Protection information Administrative status information The definitive guide to Enterprise and Carrier Metro Ethernet applications. Separation of control and data channels Notify messages Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization The following sections describe the different enhancements to signaling introduced by GMPLS. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts

LSP Hierarchy—Signaling
Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures section, GMPLS supports the concept of As already explained in the "LSP Hierarchy—Routing" hierarchical LSPs, which allows multiple LSPs to be nested; that is, it allows newly initiated LSPs Metro networks will emerge as the next area of growth for the networking industry and will to be aggregated within existing LSPs. The newly initiated LSPs are tunneled inside an existing represent a major shift in how data services are offered to businesses and residential customers. higher-order LSP, which becomes a link along the path of the new LSP. This dramatically The metro has always been a challenging environment for delivering data services because it has enhances network scalability and manageability because it minimizes the number of elements been built to handle the stringent reliability and availability needs for voice. Carriers will have to that are flooded and advertised within the network. This section explains the signaling aspect of go through fundamental shifts to equip the metro for next-generation data services demanded the LSP hierarchy. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow thethe incumbent carriers to transform metro to To give an example of how GMPLS signaling uses LSP hierarchy, assume that a the certain router offer enhanced data services. requests bandwidth to be allocated along a network consisting of data switches, SONET crossconnects, WDM-capable switches, and fiber switches. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the edge current metro, which is based TDM technology, and discusses The request from the router to establish a PSC on LSP with a certain bandwidth couldthe trigger drivers and challenges carriers will face in transforming the metro to address data services. the establishment of multiple higher-order LSPs that get initiated by other switches along the path. Lower-order LSPs (the new LSPs) get nested inside the higher-order LSPs that already Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers exist or that get triggered based on the edge router's request. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and into the role of virtual private networks Figure 8-7 shows the establishment of a series of delves LSPs along a path that consists of routers (R0, (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic R1, R8, and R9), SONET ADMs (S2 and S7), WDM Optical Electrical Optical (OEO) switches (W3 engineering, and MPLS and Generalized MPLS (GMPLS). and W6), and fiber switches (F4 and F5). A PATH request, path 0, needed for the formation of LSP0 between R0 and R9, is sent from R0 to R1. At router R1, this triggers the initiation of LSP1 between R1 and R8. LSP1 is nested inside LSP0. The PATH messages—path1, path2, and path3—continue to propagate, and the LSPs keep getting created until the final establishment of LSP0 between R0 and R9.

Figure 8-7. Initiation of New Nested LSPs
[View full size image]

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Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that has enables networking professionals of all levels to An LSP is established when the path message completed its path inside higher-level LSPs understand the concepts and a RESV message is received. Note in Figure 8-8 how LSP3, the higher-level LSP, gets established first, then LSP2 gets established inside LSP3, then LSP 1 inside LSP2, and LSP 0 Gain from the experience of industry innovator and best-selling Cisco Press author, Sam inside LSP1. Halabi, author of Internet Routing Architectures

Figure 8-8. Nested Metro networks will emerge as the next area of growth for LSPs the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services.
Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Now assume that a carrier is offering an Ethernet packet transport service between two service providers—ISP1 and ISP2—with an SLA set to 200 Mbps. For simplicity, assume that the carrier's end-to-end network is formed via routers (R0, R1, R8, and R9), SONET ADMs (S2 and S7), WDM OEO switches (W3 and W6), and fiber switches (F4 and F5). Also, for the sake of simplicity, the GE service for the carrier is assumed to be point-to-point between R0 and R9, meaning that all traffic that comes in on the GE links of R0 comes out on the GE links of R9. Physical connectivity is done in the following way:
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Metro Ethernet BySamR1-S2 Halabi

Table of Contents

R0-R1 Index and R8-R9— Ethernet GE (1 Gbps) link and R8-S7— OC48c (2.4 Gbps) packet over SONET (PoS) link

Publisher: Cisco Press

S2-W3 and S7-W6— OC192 (9.6 Gbps) TDM link 16 OC192 lambdas

Pub Date: October 2003 W3-F4 and 01, W6-F5— ISBN: 1-58705-096-X

F4-F5— Pages: 24016 fibers, carrying 16 OC192 lambdas each The following illustrates the process of LSP creation on all the boxes between ISP1 and ISP2: LSP0 between R0 and R9 as a 200-Mbps connection The definitive guide to Enterprise and Carrier Metro Ethernet applications. LSP1 between R1 and R8 as an OC48c connection Discover the latest developments in metro networking, Ethernet, and MPLS services and LSP2 between S2 and S7 as an OC192 connection what they can do for your organization LSP3 between W3 and W6 as a lambda connection Learn from the easy-to-read format that enables networking professionals of all levels to understand LSP4 between the P4 concepts and P5 as a fiber connection LSP0 Gain is nested frominside the experience LSP1, LSP1 of is industry nested innovator inside LSP2, and and best-selling LSP2 is nested Cisco Press insideauthor, LSP3. Sam Halabi, author of Internet Routing Architectures In addition to the creation of the LSPs, the nodes announce the residual bandwidth available in Metro the LSP networks hierarchy will in emerge the following as themanner: next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has 1. Node R0 announces a PSC link from R0 to R9 with bandwidth equal to the difference been built to handle the stringent reliability and availability needs for voice. Carriers will have to between the GE link and 200 Mbps—that is, 800 Mbps. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the 2. Node R1 announces a PSC link R1 tothe R8 incumbent with bandwidth equal to the difference operational and business model that from will allow carriers to transform the metro to between the OC48c capacity (2.4 Gbps) and 200 Mbps—that is, 2.2 Gbps. offer enhanced data services. 3. Node S2 announces aPress TDM link from S2 deployment to S7 with bandwidth equal to the difference Metro Ethernet from Cisco looks at the of metro data services from a holistic between the OC192 (STS-192) link capacity and the allocated OC48 (STS-48) time view. It describes the current metro, which is based on TDM technology, and discusses the slots—that is, STS-144. drivers and challenges carriers will face in transforming the metro to address data services. 4. Node W3 announces an LSC link from W3 to W6 with bandwidth to the difference Metro Ethernet discusses the adoption of metro Ethernet services and equal how that has led carriers between 16 lambdas and the allocated lambda—that is, 15 lambdas. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks 5. Node P4 announces an FSC link from P4 to P5 with bandwidth equal to the difference (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic between 16 fibers and the allocated fiber—that is, 15 fibers. engineering, and MPLS and Generalized MPLS (GMPLS). As part of enhancements to signaling, GMPLS introduces enhancements to the MPLS label itself, as described next.

Enhancements to Labels

GMPLS introduces new label concepts to accommodate the specific requirements of the optical space. The new concepts include the generalized label, the label set, and the suggested label.

The Generalized Label
• Table of Contents • Index the scope of GMPLS that includes non-packet/cell interfaces, several new forms To accommodate Metro Ethernet of labels are required, which are called generaliz ed labels. A generalized label extends the traditional BySam Halabilabel by allowing the label to identify time slots, wavelengths, or space-division multiplexed positions. Examples are label representation of a fiber in a bundle, a waveband within a fiber, a wavelength in a waveband, and a set of time slots within a wavelength, as well Publisher: Cisco Press as the traditional MPLS label. The generalized label has enough information to allow the Pub Date: October 01, 2003 receiving node to program a cross-connect regardless of the type of the cross-connect. As you ISBN: 1-58705-096-X have already seen in Chapter 7, "MPLS Controlling Optical Switches," the label is purely a Pages: 240 signaling construct used to give information about how interfaces are cross-connected and is not part of the forwarding plane.

An example of a SONET/SDH label format is shown in Figure 8-9. This is an extension of the (K, L, M) numbering scheme defined in ITU-T Recommendation G.707, "Network Node Interface for the Digital Hierarchy" (October The S, U,applications. K, L, and M fields help identify the The Synchronous definitive guide to Enterprise and Carrier 2000). Metro Ethernet signals in the SONET/SDH multiplex. Each letter indicates a possible branch number starting at the parent node in the SONET/SDH multiplex structure. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do Figure for your organization 8-9. SONET/SDH Label Format Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures A generalized label used to communicate the for characteristics required to support Metro networks will request emerge is as the next area of growth the networking industry and willthe LSP being a requested. The carried in the generalized label request includes the represent major shift in information how data services are offered to businesses and residential customers. following: The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded LSP Encoding Type— 8-bit field that indicates LSP encoding types, such packet, by enterprise customers and An consumers. This is not only the a technology shift, but also a as shift in the Ethernet, PDH, SDH, SONET, Digital Wrapper (DW), lambda, fiber, and Fiber Channel. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. When a generalized label request is made, the request carries an LSP encoding type that Cisco indicates the typeat ofthe thedeployment LSP, such as SONET, SDH, Gigabit from Ethernet, Metroparameter Ethernet from Press looks of metro data services a holistic lambda, fiber, and so on. The lambda encoding type, for example, refers to an LSP that view. It describes the current metro, which is based on TDM technology, and discusses the encompasses a whole wavelength. The fiber encoding type refers to an LSP that drivers and challenges carriers will face in transforming the metro to address data services. encompasses a whole fiber port. The encoding type represents the type of the LSP and not naturediscusses of the links the LSP traverses. AEthernet link mayservices support and a set of encoding formats Metrothe Ethernet the adoption of metro how that has led carriers where theof link can carry and switch a signal of one or more of these encoding formats to the delivery metro data services. With a changing mix of transport technologies, the book depending on the and link's resourcetrends, availability and capacity. then examines current emerging and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Switching An Generalized 8-bit field that indicates the type of switching that should be engineering, andType— MPLS and MPLS (GMPLS). performed on a particular link. This field is needed for links that advertise more than one type of switching capability, such as PSC, L2SC, TDM, LSC, and FSC. Generalized Payload Identifier (G-PID)— A 16-bit field used by the nodes at the endpoint of the LSP to identify the payload carried by the LSP. Examples of the PID are standard Ethertype values for packet and Ethernet LSPs. Other values include payload

types such as SONET, SDH, Digital Wrapper (DW), STS, POS, ATM mapping, and so on. A generalized label carries only a single level of labels—that is, the label is nonhierarchical. When multiple levels of labels are required, each LSP must be established separately, as discussed in the previous section "LSP Hierarchy—Signaling."

Waveband Switching Support • Table of Contents
• Index

Awaveband represents a set of contiguous wavelengths that can be switched together to a new Metro Ethernet waveband. For optimization reasons, it may be desirable for an OXC to optically switch multiple BySam Halabi wavelengths as a unit. This may reduce the distortion on the individual wavelengths and allow tighter separation of the individual wavelengths. The waveband label is defined to support this Publisher: Cisco Press special case.
Pub Date: October 01, 2003

Waveband ISBN: switching 1-58705-096-X uses the same format as the generalized label. Figure 8-10 shows the format of the generalized label in the context of waveband switching. Pages: 240

Figure 8-10. Generalized Label—Waveband Switching
The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to The Label Set go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the The label setand is used to restrict the label that may be used for a to particular LSP between operational business model that willranges allow the incumbent carriers transform the metro to two The receiver of a label set must restrict its choice to one label range that is in the offerpeers. enhanced data services. label set. The label set is useful in the optical domain because of the restrictions on how optical equipment allocates and handles wavelength conversion, restricts the use of Metro Ethernet from wavelengths Cisco Press looks at the deployment of metro datawhich services from a holistic labels that are bound thesemetro, wavelengths. Reasons for using the label set include the the following: view. It describes the to current which is based on TDM technology, and discusses drivers and challenges carriers will face in transforming the metro to address data services. end equipment receive only on a small, specific set of MetroThe Ethernet discusses can the transmit adoption and of metro Ethernet services and how that has led carriers wavelengths/bands. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks There is a sequence ofarea interfaces that cannot virtual support wavelength conversion and that (VPN), virtual private local networks (VLAN), private LAN services (VPLS), traffic requires the same wavelength to be used end-to-end over a sequence of hops or an entire engineering, and MPLS and Generalized MPLS (GMPLS). path. For operators, it is desirable to limit the amount of wavelength conversion being performed to reduce the distortion of the optical signals. The two ends of a link support different sets of wavelengths.

The use of a label set is optional, and if it is not present, it is assumed that all labels can be used.

The Suggested Label
GMPLS allows an upstream • Table of Contents node to suggest a label to the downstream (one hop away) node for different optimization purposes that are specific to optical networks. The downstream node may • Index override the suggested label at the expense of higher LSP setup times and perhaps suboptimal Metro Ethernet allocation of network resources. A typical example is when an optical switch configures its own BySam Halabi label to adjust its mirrors and save valuable time before the downstream switch allocates the label. Other examples involve any activity where there is latency in configuring the switching Publisher: Cisco Press fabric.
Pub Date: October 01, 2003

Early configuration can reduce setup latency and may be important for restoration purposes ISBN: 1-58705-096-X wherePages: alternate LSPs may need to be rapidly established as a result of network failures. 240

Bandwidth Encoding
GMPLS LSPs support packet or nonpacket LSPs. For Ethernet nonpacket LSPs, it is useful to list the The definitive guide to Enterprise and Carrier Metro applications. discrete bandwidth value of the LSP. Bandwidth encoding values include values for DS0 to OC768, E1 to STM-256, 10/100/1000/10,000-Mbps Ethernet, and 133- to 1062-Mbps Fiber Channel. Discover The bandwidth the latest developments encodings are in carried metroin networking, protocol-specific Ethernet, (RSVP-TE, and MPLS CR-LDP) services objects. and Examples what of they RSVP-TE can doare for the your SENDER_TEMPLATE organization and FLOW_SPEC objects. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Bidirectional LSPs Gain from the experience of industry innovator and best-selling Cisco Press author, Sam ManyHalabi, optical author serviceof providers bidirectional optical LSPs a requirement, because many Internet consider Routing Architectures of the underlying constructs for SONET/SDH networks are inherently bidirectional. It is assumed that bidirectional LSPs have as the same TE requirements fate sharing, protection, Metro networks will emerge the next area of growth (including for the networking industry and willand restoration) and resource (such as offered latencyto and jitter) in each direction. customers. represent a major shift in requirements how data services are businesses and residential The metro has always been a challenging environment for delivering data services because it has The traditional MPLSthe LSPstringent establishment is unidirectional. Establishing a bidirectional been built to handle reliability and availability needs for voice. Carriers LSP will have to requires establishing two unidirectional LSPs, which has many disadvantages: go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to The latency to establish the bidirectional LSP is equal to one round-trip signaling time plus offer enhanced data services. one initiator-terminator signaling transit delay. This extends the setup latency for LSP establishment andat extends the worst-case latency discovering an Metrosuccessful Ethernet from Cisco Press looks the deployment of metro datafor services from a holistic unsuccessful LSP. These delays are particularly significant for LSPs that are established view. It describes the current metro, which is based on TDM technology, and discusses the for restoration purposes. drivers and challenges carriers will face in transforming the metro to address data services. control overhead of adoption two unidirectional is twice that and of one bidirectional LSP, MetroThe Ethernet discusses the of metro LSPs Ethernet services how that has led carriers because separate control messages must be generated for each unidirectional LSP. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks Because the resources are established in separate segments, route selection gets (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic complicated. Also, if the resources needed to establish the LSP are not available, one engineering, and MPLS and Generalized MPLS (GMPLS). unidirectional LSP gets established, but the other doesn't. This decreases the overall probability of successful establishment of the bidirectional connection. SONET equipment in particular relies on hop-by-hop paths for protection switching. SONET/SDH transmits control information in-band. This requires connections to be paired, meaning that bidirectional LSP setup is highly desirable. Therefore, GMPLS supports

additional methods that allow bidirectional LSP setup, to reduce session establishment overhead.

Notification of Label Error
Some situations in traditional MPLS and GMPLS result in an error message containing an • Table of Contents "Unacceptable label value" indication. When these situations occur, it is useful if the node that is • Index generating the error message indicates which labels are acceptable. To cover these situations, Metro Ethernet GMPLS introduces the ability to convey such information via an acceptable label set. An acceptable BySam Halabi label set is carried in appropriate protocol-specific error messages. The format of an acceptable label set is identical to a label set, as described earlier in this Publisher: Cisco Press chapter in the section "The Label Set."
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 Control Explicit Label

As discussed in Chapter 7, with RSVP-TE, the interfaces used by an LSP may be controlled by an explicit route via the ERO or ERO hop. This allows the LSP to control which nodes/interfaces it goes in and out on. The problem is that the ERO and ERO hop do not support explicit label The definitive guide to Enterprise and Carrier Metro Ethernet applications. subobjects, which means that they cannot support the granularity needed by optical networks. For example, in networks that are not packet-based, LSPs sometimes need to be spliced together. This means that the tail end of an LSP needs to be spliced with the head end of another Discover the latestthe developments in metro hop networking, Ethernet, and MPLS servicesroutes. and LSP. GMPLS introduces ERO subobject/ERO to allow finer granularity for explicit what they can do for your organization

Protection Information understand the concepts

Learn from the easy-to-read format that enables networking professionals of all levels to

Gain from the object experience of industry innovator and Cisco Press author, Sam GMPLS uses a new type length value (TLV) field tobest-selling carry LSP protection information. The Halabi, author of Internet Routing Architectures use of this information is optional. Protection information indicates the LSP's link protection type. When a protection type is indicated, the connection request is processed only if the desired Metro networks will be emerge as the next area of growth for the networking industry and will protection type can honored. A link's protection capabilities may be advertised in routing. represent a major shift in how data services are offered to businesses and residential customers. The metro information has always been a challenging environment for delivering services because it has Protection also indicates whether the LSP is a primary or data secondary LSP. A been built to handle the stringent reliability and needs for voice. Carriers will have to secondary LSP is a backup to a primary LSP. Theavailability resources of a secondary LSP are not used until go through shifts to equip the metro for next-generation data services demanded the primaryfundamental LSP fails. The resources allocated for a secondary LSP may be used by other LSPs by enterprise customers and consumers. This is not only a technology shift, but alsothat a shift until the primary LSP fails over to the secondary LSP. At that point, any set of LSPs arein the operational and business model that will allow the carriers to transform the metro to using the resources for the secondary LSP must be incumbent preempted. offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Administrative Status Information view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. GMPLS introduces a new object/TLV for administrative status information. The use of this information is optional. The information can be used in two ways: and how that has led carriers Metro Ethernet discusses the adoption of metro Ethernet services to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks To indicate the LSP's such as "Administratively down," "testing," or (VPN), virtual private localadministrative area networks state, (VLAN), virtual private LAN services (VPLS), traffic "deletion in progress." The nodes can use this information to allow local decisions, such as engineering, and MPLS and Generalized MPLS (GMPLS). making sure an alarm is not sent if the LSP is put in a test mode. In RSVP-TE, this object is carried in the PATH and RESV messages. To send a request to set the LSP's administrative state. This request is always sent to the ingress nodes that act on the request. In RSVP-TE, this object is carried in a Notify message (discussed later, in the section "Notify Messages").

Separation of Control and Data Channels
In optical networks, the control and data channels need to be separated for multiple reasons, including these:
• •

Multiple links can be bundled. Index Some data channels cannot carry control information. The integrity of a data channel does not affect the integrity of control channels.

Table of Contents

Metro Ethernet BySam Halabi

The following two sections discuss two critical issues for the separation of data and control Pub Date: October 01, 2003 channels.
ISBN: 1-58705-096-X Pages: 240

Publisher: Cisco Press

Interface Identification
In MPLS, a one-to-one association exists between the data and control channels (except for MPLS link bundling). In GMPLS, where such association does not exist, it is necessary to convey The definitive guide to Enterprise and Carrier Metro Ethernet applications. additional information in signaling to identify the particular data channel being controlled. GMPLS supports explicit data channel identification by providing interface identification information. GMPLS allows the use of several interface identification schemes, including IPv4 Discover the latest developments in metro networking, Ethernet, and MPLS services and or IPv6 addresses, interface indexes, and component interfaces (established via configuration or a what they can do for your organization protocol such as LMP). In all cases, the choice of the data interface is indicated by the addresses and identifiers used the upstream node. Learn from the by easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Fault Handling Halabi, author of Internet Routing Architectures Two new faults must be handled when the control channel is independent of the data channel: Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data because it has Control channel fault— A link or other type of failure that limits theservices ability of neighboring been nodes built to handle the stringent reliability and availability needs for voice. Carriers will have to to pass control messages. In this situation, neighboring nodes are unable to go through fundamental shifts to equip the metro for next-generation data services demanded exchange control messages for a period of time. Once communication is restored, the by enterprise customers and consumers. This is not only technology shift, but also a shift underlying signaling protocol must indicate that thea nodes have maintained their statein the operational and business model that will allow the incumbent carriers to transform the metro through the failure. The signaling protocol must also ensure that any state changes that to offer were enhanced data services. instantiated during the failure are synchronized between the nodes. MetroNodal Ethernet fromA Cisco Press looks at the deployment of metro data services holistic fault— node's control plane fails and then restarts and loses mostfrom of itsastate view.information It describesbut thedoes current metro, which is based on TDM technology, and discusses the not lose its data forwarding state. In this case, both upstream and drivers and challenges carriers will face in transforming the metrowith to address data services. downstream nodes must synchronize their state information the restarted node. For any resynchronization to occur, the node undergoing the restart needs to preserve some Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers information, such as its mappings of incoming labels to outgoing labels. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Notify Messages engineering, and MPLS and Generalized MPLS (GMPLS). GMPLS provides a mechanism to inform nonadjacent nodes of LSP-related failures using Notify messages. In optical networks, failure notification sometimes has to traverse transparent nodes to notify the nodes responsible for restoring failed connections (transparent nodes do not originate or terminate connections). This mechanism enables target nodes to be notified directly

and more quickly of a network failure. The Notify message has been added to RSVP-TE. The Notify message includes the IP address of the node that needs to be notified. Other nodes in the path just pass on the message until it reaches the targeted node. The Notify message differs from the error messages Path-Error and Reservation-Error in that it can be "targeted" to a node other than the immediate upstream and downstream neighbor. Another application of the Notify message is to notify when the control plane has failed while the data plane is still functional. GMPLS uses this mechanism to identify degraded links.
• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Inclusion of Technology-Specific Parameters
The previous sections discussed the enhancements to signaling that allow GMPLS to control the different types of packet and nonpacket networks. GMPLS also allows the inclusion of technology-specific parameters that are carried in the signaling protocol in traffic • Table of objects. Contents This section looks at how this applies to SONET/SDH. A description parameter–specific • Index of parameters that are specific to optical transport network (OTN) technology is not included in Metro Ethernet this book.
BySam Halabi

The SONET/SDH traffic parameters specify a set for SONET (ANSI T1.105) and a set for SDH (ITU-T G.707), such as concatenation and transparency. Other capabilities can be defined and Publisher: Cisco Press standardized as well. These traffic parameters must be used when SONET/SDH is specified in the Date: October 01, 2003 LSPPub Encoding Type field of a generalized label request, discussed earlier in the section "The ISBN: Generalized1-58705-096-X Label." The SONET/SDH traffic parameters are carried in the SENDER_TSPEC and Pages: 240 FLOWSPEC objects of RSVP-TE and in SONET/SDH TLVs in CR-LDP. Figure 8-11 shows how the SONET/SDH traffic parameters are organized. The Signal Type indicates the type of the elementary signal of the request LSP. Several parameters can be applied on the signal to build the final requested signals. These parameters are applied using the Request Contiguous Concatenation (RCC), Number Contiguous Components (NCC), and The definitive guide to Enterprise and Carrier Metroof Ethernet applications. Transparency fields included in the traffic parameter. Discover the latest developments in metro networking, Ethernet, and MPLS services and Figure 8-11. SONET/SDH Traffic Parameters what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Examples of signal types for SONET/SDH include VT1.5, VT2, VT3, VT6, STS1, VC-11, VC-12, go through fundamental shifts to equip the metro for next-generation data services demanded VC2, VC-3, and VC-4, plus other possible types, depending on the level of concatenation and by enterprise customers and consumers. This is not only a technology shift, but also a shift in the transparency. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. The RCC field, the NCC field, and the Number of Virtual Components (NVC) field are used to negotiate the type of concatenation and the number of signals that are to be concatenated. As Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic mentioned in Chapter 2, "Metro Technologies," concatenation can be applied to signals to form view. It describes the current metro, which is based on TDM technology, and discusses the larger signals. Different types of concatenation, such as contiguous or virtual, can be applied, drivers and challenges carriers will face in transforming the metro to address data services. and the information is related in the signaling protocol. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic NOTE engineering, and MPLS and Generalized MPLS (GMPLS). Transparency, in the context of SDH/SONET signals, refers to the overhead signals, such as the section overhead (SOH) and the line overhead (LOH) in the case of SONET. Transparency indicates which of these overhead fields needs to remain untouched when delivered to the other end of the LSP.

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Link Management Protocol
Future networks may consist of optical switches, data switches that are managed by GMPLS. Thousands of fibers may connect a pair of nodes, and hundreds of wavelengths may exist on each fiber. Multiple fibers and wavelengths can be bundled to form TE links. These links need a • Table Contents routing, signaling, and link connectivity and management. LMP is a control channel toof manage • Index link-control protocol that runs between neighboring nodes to manage TE links.
Metro Ethernet

LMP was created to address the issues of link provisioning and fault isolation to improve and BySam Halabi scale network manageability. With GMPLS, the control channel between two adjacent nodes is no longer required to use the same physical medium as the data channels between those nodes. A Publisher: Cisco Press control channel can run on a separate IP management network, a separate fiber, or a separate Pub Date: October 01, 2003 wavelength. LMP allows for the decoupling of the control channel from the component links. As ISBN: 1-58705-096-X such, the health of the control channel does not necessarily correlate to the health of the data 240 versa. links, Pages: and vice LMP is designed to provide four basic functions to a node pair: Control channel management— A core function of LMP that is used to establish and The definitive tochannel Enterprise and Carrier Metro Ethernet applications. maintain guide control connectivity between neighboring nodes. This consists of lightweight Hello messages that act as a fast keepalive mechanism between the nodes. Discover the latest developments in metro networking, Ethernet, and MPLS services and Link connectivity verification— An optional LMP function that is used to verify physical what they can do for your organization connectivity of the data-bearing channels between the nodes and to exchange the interface IDs that are used in GMPLS signaling. The error-prone manual cabling procedures make Learn from the easy-to-read format that enables networking professionals of all levels to LMP link connectivity verification very useful. understand the concepts Link property correlation— A core innovator function ofand LMP that is designed aggregate Gain from the experience of industry best-selling Cisco to Press author,multiple Sam ports or component links into a TE link and to synchronize the properties of the TE link. Halabi, author of Internet Routing Architectures Link properties, such as link IDs for local and remote nodes, the protection mechanism, and priority, can beemerge exchanged via LMParea using LinkSummary message industry between and adjacent Metro networks will as the next ofthe growth for the networking will nodes. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has management and isolation— optional LMP needs function provides a mechanism been Fault built to handle the stringent reliability An and availability forthat voice. Carriers will have to to isolate link and channel failures in both opaque and transparent networks, go through fundamental shifts to equip the metro for next-generation data servicesirrespective demanded of the data customers format. Opaque nodes are nodes channels can beshift, terminated for by enterprise and consumers. This iswhere not only a technology but also a the shift in the purpose of examining the headers and data. Transparent nodes are nodes where operational and business model that will allow the incumbent carriers to transform the channels metro to through without termination. offer pass enhanced data services. LMP requires that a pair of Press nodes haveat at the least one active of bidirectional channel Metro Ethernet from Cisco looks deployment metro datacontrol services from a between holistic them. This control channel may be implemented using two unidirectional control channels view. It describes the current metro, which is based on TDM technology, and discusses thethat are coupled using the LMP Hello messages. LMP allows backup control channels to be defined, drivers and challenges carriers will face in transforming the metro to address data services. such as using the data-bearing channels as backup in case of failure in the primary control channels. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

GMPLS Protection and Restoration Mechanisms
GMPLS introduces the necessary features in routing, signaling, and link management to support the fault management required in optical and electronic networks. Fault management requires the following capabilities:
• • Table of Contents Index

detection— Metro Fault Ethernet

For optical networks, fault detection can be handled via mechanisms such as loss of light (LOL) and optical signal-to-noise ratio (OSNR) at the optical level, and BySam Halabi bit error rate (BER), SONET/SDH Alarm Indicator Signal (AIS), or LOL at the SONET/SDH level.
Publisher: Cisco Press Pub Date: October 01, 2003 Fault isolation— For

GMPLS, LMP can be used for fault isolation. The LMP faultmanagement ISBN: 1-58705-096-X procedure is based on sending ChannelActive and ChannelFail messages over the control channel. The ChannelActive message is used to indicate that one or more dataPages: 240 bearing channels are now carrying user data. The ChannelFail message is used to indicate that one or more active data channels or an entire TE link has failed.

Fault notification— GMPLS uses the RSVP-TE Notify message to notify nodes of any possible failures. The Notify message can be used over the data-bearing links to indicate a The definitive to Enterprise and Carrier Metro Ethernet failure in guide the control plane, or over the control channels applications. to indicate a failure in the data plane. The notify request object can be carried in the RSVP PATH or RESV messages and indicates the latest IP address of the node that should be notified when and generating an error Discover the developments in metro networking, Ethernet, MPLS services and message. what they can do for your organization GMPLS uses the following protection mechanisms: Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts 1+1 protection— The data is transmitted simultaneously over the two disjoint paths. The Gain from the experience of industry innovator and best-selling Cisco Press author, Sam receiver selects the working path based on the best signal. Halabi, author of Internet Routing Architectures 1:1 protection— A dedicated backup path is preallocated to protect the primary path. Metro networks will emerge as the next area of growth for the networking industry and will represent major shift in data services offered to businesses and residential customers. M:N a protection— Mhow backup paths are are preallocated to protect N primary paths. However, The metro has always been a challenging environment for delivering data services because it has data is not replicated onto a backup path, but only transmitted in case of failure on the been primary built to handle the stringent reliability and availability needs for voice. Carriers will have to path. go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This paths is not may only be a technology shift, but also a shift in the For 1:1 and M:N protection, the backup used by other LSPs. For 1+1 operational and business model that will allow the incumbent carriers to transform the protection, the backup paths may not be used by other LSPs because the data is metro to offer transmitted enhanced data on services. both paths. MetroSpan Ethernet from Cisco Press looks at the deployment of metro that datarequires services switching from a holistic protection— Intermediate nodes initiate the recovery to an view.alternative It describes the current which is based extensions, on TDM technology, and discusses path. As part metro, of the GMPLS routing the link protection typethe is drivers and challenges will face in transforming the metro to address data services. advertised so thatcarriers span protection can be used. MetroSpan Ethernet discusses the adoption of metro Ethernet and how that has led carriers restoration— Intermediate nodes initiate theservices recovery that requires switching to an to the delivery of metro data services. With a changing mix of transport technologies, the book alternative path. The alternative path is dynamically computed. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtualthat private LAN services (VPLS), traffic Path protection— End nodes initiate the recovery requires switching to an alternative engineering, and MPLS and Generalized MPLS (GMPLS). path. The end nodes switch to the backup path. Path restoration— End nodes initiate the recovery that requires switching to an alternative path. The backup path is dynamically calculated upon failure.

Summary of Differences Between MPLS and GMPLS
As you've learned in this chapter, GMPLS extends MPLS to support non-packet/cell interfaces. The support of the additional TDM, lambda, and fiber interfaces impacts the basic LSP properties, such as how labels are requested and communicated and the unidirectional LSP • Table of Contents and so on. behavior, error propagation,
•
BySam Halabi

Index

Metro Ethernet Table 8-1 summarizes the basic differences between MPLS and GMPLS described in this chapter.

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Table 8-1. Differences Between MPLS and GMPLS
GMPLS Supports packet/cell, TDM, lambda, and fiber.

MPLS

Supports packet/cell-based interfaces only.

LSPs start and end on LSPs start and end on "similar type" LSRs (that is, PSC, L2SC, The definitive guide to Enterprise and Carrier Metro Ethernet applications. packet/cell LSRs. TDM, LSC, FSC). Bandwidth allocation can be Bandwidth allocation can only be done in discrete units for some Discover the latest developments in metro networking, and MPLS services and done in any number of units. switching capabilities such asEthernet, TDM, LSC, and FSC. what they can do for your organization Typical large number of Fewer labels are allocated when applied to bundled links. Learn from the easy-to-read format that enables networking professionals of all levels to labels. understand the concepts No restrictions on label use An ingress or upstream node may restrict the labels that may be by upstream nodes. used by aninnovator LSP alongand a single hop or Cisco the whole path. This is Gain from the experience of industry best-selling Press author, Sam used, for example, to restrict the number of wavelengths that Halabi, author of Internet Routing Architectures can be used in the case where optical equipment provides a Metro networks will emerge as the small next number area of ofgrowth wavelengths. for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. Only one label format. Use of a specific label on a delivering specific interface. The metro has always been a challenging environment for data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to Label formats depend on the specific interface used, such as go through fundamental shifts to equip the metro for next-generation data services demanded PSC, L2SC, TDM, LSC, FSC. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business that will allow the incumbent carriers to in transform the metro to Labels are used for data model Labels are a control plane construct only GMPLS and are not offer enhanced data forwarding and are services. carried part of the traffic. within the traffic. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic No need for technologySupports the technology-specific in view. It describes the current metro, which isinclusion based onof TDM technology, and parameters discusses the specific parameters, because signaling. drivers and challenges carriers will face in transforming the metro to address data services. this is applied to packet/cell Metro interfaces Ethernet only. discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Data and control channels Separation of and control andinto data channels then examines current and emerging trends, delves the role of virtual private networks follow the same path. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLSmechanism (GMPLS). for rapid failover (Notify message) MPLS fast-reroute. RSVP-specific

Unidirectional LSPs.

Bidirectional LSPs enable the following: Possible resource contention when allocating reciprocal LSPs via separate signaling sessions Simplified failure restoration procedures

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Lower setup latency Lower number of messages required during setup Allow a label to be suggested by an upstream node and can be overwritten by a downstream node (to prevent delays with setting optical mirrors, for example)

Labels cannot be suggested by upstream node.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
As you have seen in this chapter, many extensions for routing, signaling, technology-specific parameters, and LMP allow the use of MPLS over non-packet/cell networks. Mechanisms such as link bundling and shared link groups are added to routing to influence the traffic trajectory and • Table of Contents to take advantage of how the physical network topology is laid out. Signaling mechanisms such • Index as the enhancements to the label allow the GMPLS label to be used as a control construct that Metro Ethernet indicates to the TDM/optical devices what circuits to switch and how to switch them. The introduction By Sam Halabi of LMP helps in the easy provisioning and protection of optical circuits by allowing channel link connectivity verification and fault management and isolation.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Appendix A. SONET/SDH Basic Framing and Concatenation
• Table of Contents This appendix discusses the following topics: •
Metro Ethernet BySam Halabi

Index

SONET/SDH Frame Formats SONET/SDH Architecture

Publisher: Cisco Press

SONET/SDH Concatenation Pub Date: October 01, 2003 This appendix explains basic SONET/SDH framing and concatenation. With the emergence of L2 Pages: 240 metro services, SONET/SDH metro networks are being challenged to offer cost-effective and bandwidth-efficient solutions for transporting data services. The following sections describe the different elements of a SONET/SDH frame and how the elements can be combined to form bigger SONET/SDH pipes. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).
ISBN: 1-58705-096-X

SONET/SDH Frame Formats
The fundamental signal in SONET is the STS-1, which operates at a rate of about 51 Mbps. The fundamental signal for SDH is STM-1, which operates at a rate of about 155 Mbps (three times the STS-1 rate). The signals are made of contiguous frames that consist of two parts: the • Table of Contents transport overhead (TOH) contained in the header, and the payload. For synchronization • Index purposes, the data can be allowed to shift inside the payload inside a Synchronous Payload Metro Ethernet Envelope (SPE) for SONET and inside the Virtual Container for SDH. The SPE inside the payload is Sam referenced By Halabi using a pointer. Figures A-1 and A-2 show the SONET and SDH frames.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure A-1. SONET Frame Format

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Figure A-2. SDH Frame Format been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

SONET/SDH Architecture
The SONET/SDH architecture identifies three different layers, each of which corresponds to one level of communication between SONET/SDH equipment. The layers are as follows, starting with the lowest:
• •
BySam Halabi

Table of Contents Index

regenerator Metro The Ethernet

section, or section layer

The multiplex section, or line layer

Publisher: Cisco Press The path layer Pub Date: October 01, 2003

Figure ISBN: A-3 shows the three SONET/SDH layers. 1-58705-096-X
Pages: 240

Figure A-3. SONET and SDH Layers
[View full size image]

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures As shown in Figures A-1 and A-2, each of these layers in turn has its own overhead (header). Metro networks will emerge as the next area of growth for the networking industry and will The transport overhead (TOH) of a SONET/SDH frame is mainly subdivided into two parts that represent a major shift in how data services are offered to businesses and residential customers. contain the section overhead (SOH) and the line overhead (LOH). In addition, a pointer indicates The metro has always been a challenging environment for delivering data services because it has the beginning of the SPE/Virtual Container in the payload of the overall frame. The SPE/Virtual been built to handle the stringent reliability and availability needs for voice. Carriers will have to Container itself is made up of the path overhead (POH) and a payload. This payload can be go through fundamental shifts to equip the metro for next-generation data services demanded further subdivided into subelements, or a multiplex structure (signals). This multiplex structure by enterprise customers and consumers. This is not only a technology shift, but also a shift in the leads to identifying time slots that contain tributary signals such as T1 (1.5 Mbps), E1 (2 Mbps), operational and business model that will allow the incumbent carriers to transform the metro to and so on. For example, a SONET STS-1 can be further divided into 7 * VT-6 (virtual offer enhanced data services. tributaries), where VT-6 is equal to 6.321 Mbps. A VT-6 can be divided into 4 * VT 1.5, where a VT-1.5 is 1.544 from MbpsCisco or a T1. Figure A-4 shows the SONET structure. Figures A-5 Metro Ethernet Press looks at the deployment of multiplexing metro data services from a holistic and A-6 show the SDH multiplexing structure. Table A-1 shows some helpful mapping between view. It describes the current metro, which is based on TDM technology, and discusses the SONET and challenges SDH. drivers and carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet servicesMultiplexing and how that has led carriers Figure A-4. SONET High-Order and Low-Order Structure to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks [View (VLAN), full size virtual image] private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Figure A-5. SDH High-Order Multiplexing Structure
[View full size image]

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will Figure A-6. SDH Low-Order Multiplexing Structure represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to [View full size image] go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Table A-1. Helpful SONET/SDH Equivalency
SONET STS-1 STS-3c
•VT-6 • Table of Contents Index

SDH VC-3 VC-4 VC-2 STM-0 STM-1

VT-3Ethernet Metro
BySam Halabi

VT-2

VC-12 VC-11 VC-4-4c VC-4-16c VC-4-64c VC-4-256c STM-4 STM-16 STM-64 STM-256

VT-1.5 Publisher: Cisco Press STS-12c
Pub Date: October 01, 2003 ISBN: 1-58705-096-X

STS-48c Pages: 240 STS-192c STS-768c

The definitive guide to Enterprise and Carrier Metro Ethernet applications.

NOTE

Discover the latest developments in metro networking, Ethernet, and MPLS services and whatthat they can do-12, for your Note STS-3, -48, organization -192, -768, and so on are referred to as OC-3, -12, -48, 192, and so on. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from N the experience of industry innovator andsignals best-selling Cisco Press author, An STSN /STMsignal is formed from N STS-1/STM-1 via byte interleaving. TheSam Halabi, author of Internet Routing Architectures SPEs/Virtual Containers in the N interleaved frames are independent and float according to their own clocking. This means that an STS-3 (OC3) pipe with bandwidth of about 155 Mbps is formed Metro networks will emerge as the next area of growth for the networking industry and will from three STS-1 signals. An STS-12 (OC12) pipe with bandwidth of about 622 Mbps is formed represent a major shift in how data services are offered to businesses and residential customers. from 12 STS-1 signals. The STS-1 signals are independent. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

SONET/SDH Concatenation
To transport tributary signals in excess of the basic STS-1/STM-1 signal rates, the SPEs/Virtual Containers can be concatenated—that is, glued together. In this case, their relationship with respect to each other is fixed in time, and they act as one bonded pipe.
• Table of Contents • Index Different types of concatenations are defined, including contiguous standard concatenation and Metro Ethernet virtual concatenation.
BySam Halabi

Contiguous Standard Concatenation Publisher: Cisco Press
Pub Date: October 01, 2003

Contiguous standard SONET concatenation allows the concatenation of M STS-1 signals within an ISBN: 1-58705-096-X STS-NPages: signal, 240with M <= N and M = 3, 12, 48, 192, 768, and so on in multiples of 4. The SPEs of theseM STS-1s can be concatenated to form an STS-M c. The STS-M c notation is shorthand for describing an STS-M signal whose SPEs have been concatenated (c stands for concatenated). This means that an STS-12c (OC12c) is formed from the concatenation of 12 STS-1 signals, and the 12 STS-1s act as one bonded pipe. Constraints are imposed on the size of STS-M c signals (that is, they must be a multiple of 3) and on their starting location and interleaving. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Figure A-7 shows an example of a SONET OC192 pipe (9.6 Gbps) that is multiplexed into 192 STS-1s or into four concatenated STS-48c pipes. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization

Figure A-7. Sample SONET Structure

Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book One the disadvantages of standard trends, concatenation is the lack ofrole flexibility in starting slots then of examines current and emerging and delves into the of virtual private time networks for STSM c signals and in their interleaving. This means that the provider has to deploy (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic SONET/SDH with the predefined MPLS concatenation bandwidth size and with bandwidth engineering, circuits and MPLS and Generalized (GMPLS). increments that do not match its customer needs. This leads to inefficiencies in bandwidth deployment. Virtual concatenation solves this problem.

Virtual Concatenation

Virtual concatenation is a SONET/SDH end-system service approved by the committee T1 of ANSI and ITU-T. The essence of this service is to have SONET/SDH end systems "glue" together the Virtual Containers or SPEs of separate signals rather than requiring that the signals be carried through the network as a single unit. In one example of virtual concatenation, two end systems that support this feature could essentially combine two STS-1s into a virtual STS-2c for the efficient transport of 100-Mbps Ethernet traffic. If instead these two end systems were to use standard concatenation with increments of STS-1, STS-3, and STS-12, a 100-Mbps pipe would • Table of Contents not fit into an STS-1 (51 Mbps) circuit and would have to use an STS-3c (155 Mbps) circuit, • Index therefore wasting about 55 Mbps of bandwidth. By using a virtual-concatenated STS-2c circuit Metro Ethernet (around 100 Mbps), the operator can achieve 100 percent efficiency in transporting a 100-Mbps By Sam Halabi Ethernet pipe.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X NOTE Pages: 240

The industry has suggested the use of arbitrary contiguous concatenation , which is similar in nature to virtual concatenation; however, it is applied inside the SONET/SDH network rather than the SONET/SDH end systems. Virtual concatenation will emerge as the solution of choice for next-generation data over SONET/SDH network deployments. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Conclusion
This appendix has presented the basics of SONET/SDH framing and explained how the SONET/SDH technology is being adapted via the use of standard and virtual concatenation to meet the challenging needs of emerging data over SONET/SDH networks in the metro. The • Table of Contents emergence of L2 metro services will challenge the legacy SONET/SDH network deployments and • Index will drive the emergence of multiservice provisioning platforms (MSPPs) that will efficiently Metro Ethernet transport Ethernet, Frame Relay, ATM, and other data services over SONET/SDH.
BySam Halabi

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Glossary
A
• •

B C

Table of Contents Index

Metro Ethernet BySamD Halabi

Publisher: Cisco Press Pub Date: October 01, 2003

E F

ISBN: 1-58705-096-X

G Pages: 240 I L The definitive guide to Enterprise and Carrier Metro Ethernet applications. M N Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization O Learn from the easy-to-read format that enables networking professionals of all levels to P understand the concepts Q Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures R Metro Snetworks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro T has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to U go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the V operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. W Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

A
add/drop multiplexer (ADM). A device installed at an intermediate point on a transmission line that enables new signals to come in and existing signals to go out. Add/drop multiplexing can be done with optical Table of Contents or electronic signals. The device may deal only with wavelengths, or it may convert Index between wavelengths and electronic TDM signals.

• •

Metro Ethernet BySam Halabi

adjacency. Publisher: Cisco Press
Pub Date: October 01, 2003

A relationship formed between selected neighboring routers and end nodes for the purpose ISBN: 1-58705-096-X of exchanging routing information.

Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

B
black hole. Routing term for an area of the internetwork where packets enter but do not emerge due to adverse conditions or poor system configuration within a portion of the network.
Table of Contents Index

• •

Metro Ethernet BySam Halabi Building Local Exchange Carriers (BLECs).

Publisher: Cisco Press

Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Service providers that offer broadband services to businesses and tenants concentrated in building offices.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

C
class of service (CoS). A classification whereby different data packets that belong to a certain class receive similar quality of service.
Table of Contents Index

• •

Metro Ethernet BySam Halabi burst size (CBS). committed

Publisher: Cisco Press

Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

A parameter associated with CIR that indicates the size up to which subscriber traffic is allowed to burst in profile and not be discarded or shaped.

committed information rate (CIR). The minimum guaranteed throughput that the network must deliver for the service under normal operating conditions. The definitive guide to Enterprise and Carrier Metro Ethernet applications. component link. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization A subset of a bigger link. A channel within a SONET/SDH channelized interface is an example ofthe a component link. Learn from easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam control plane. Halabi, author of Internet Routing Architectures logical plane where protocol packets exchanged fornetworking the purpose of achieving multiple Metro A networks will emerge as the next area get of growth for the industry and will functions, such as setting up paths used for packet forwarding or for managing the nodes represent a major shift in how data services are offered to businesses and residential customers. in the network. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the customer (CE) device. operationaledge and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. A device such as a switch or router that resides at the customer premises. The device could ownedfrom by the customer or the provider. Metro be Ethernet Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. customer premises equipment (CPE). Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book Terminating equipment, such as switches, routers, terminals, telephones, and modems, then examines current and emerging trends, and delves into the role of virtual private networks supplied by the telephone company, installed at customer sites, and connected to the (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic telephone company network. engineering, and MPLS and Generalized MPLS (GMPLS).

D
Data Packet Transport (DPT). A Media Access Control protocol that adds resiliency and protection to packet networks deployed in a ring topology.
Table of Contents Index

• •

Metro Ethernet BySam Halabi Transparent LAN Service (DTLS). Decoupled

Publisher: Cisco Press

A service that emulates a LAN over an IP/MPLS network, similar to VPLS. DTLS, however, proposes to remove any L2 switching from the provider edge devices and restrict the L2 Pub Date: October 01, 2003 switching to the customer edge devices.
ISBN: 1-58705-096-X Pages: 240

detour LSP. An LSP that is set up to reroute the traffic in case the main LSP fails. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Diffserv. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization A method used to classify IP packets so that different classes receive different quality of service treatment when forwarded the network. Learn from the easy-to-read format in that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

E
Ethernet LAN Service (E-LAN). A multipoint-to-multipoint Ethernet service.
• •
BySam Halabi

Table of Contents Index

Metro Ethernet Ethernet over

MPLS (EoMPLS).

An L2 tunneling technique that allows Ethernet frames to be carried over an IP/MPLS network. Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 SONET/SDH (EOS). Ethernet over

A technology that allows Ethernet packets to be transported over a SONET/SDH TDM network. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Ethernet Virtual Connection (EVC). Discover the latest developments in metro networking, Ethernet, and MPLS services and A point-to-point service. what they can do Ethernet for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Explicit Route Object (ERO). Gain from the experience of industry innovator and best-selling Cisco Press author, Sam A field author that indicates the path to be taken when traffic is forwarded. Halabi, of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

F
fiber-switch capable (FSC) interfaces. Interfaces that can forward data based on a position of the data in the real-world physical spaces. This is typical of optical cross-connects that switch traffic on the fiber or multipleTable of Contents fiber level.
Index

• •

Metro Ethernet BySam Halabi

Fixed Filter (FF).
Publisher: Cisco Press Pub Date: October 01, 2003

Reservation style that creates a distinct reservation for traffic from each sender. This style is common for applications in which traffic from each sender is likely to be concurrent and ISBN: 1-58705-096-X independent. The total amount of reserved bandwidth on a link for sessions using FF is the Pages: 240 sum of the reservations for the individual senders.

Forwarding Information Base (FIB). The definitive guide to Enterprise and Carrier Metro Ethernet applications. A data structure and way of managing forwarding in which destinations and incoming labels are associated with outgoing interfaces and labels. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization frame check sequence (FCS). format that enables networking professionals of all levels to Learn from the easy-to-read understand the concepts Extra characters added to a frame for error control purposes. Used in HDLC, Frame Relay, and other data link layer of protocols. Gain from the experience industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

G
generalized label request. An MPLS label scheme that extends the use of the MPLS label to nonpacket networks.
• •
BySam Halabi

Table of Contents Index

Metro Ethernet Generalized

Multiprotocol Label Switching (GMPLS).

A generalized MPLS control plane that allows the provisioning and protection of circuits over both packet and nonpacket networks. Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 Generic Attribute Registration Protocol (GARP).

A protocol defined by the IEEE to constrain multicast traffic in bridged Ethernet networks.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Gigabit Ethernet (GE). Standard forlatest a high-speed Ethernet, approved by the IEEE 802.3z standards committee Discover the developments in metro networking, Ethernet, and MPLS services and in 1996. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

I
incumbent local exchange carrier (ILEC). Traditional telephony company.
• •
BySam Halabi

Table of Contents Index

Metro Ethernet interexchange

carrier (IXC).

Common carrier that provides long-distance connectivity between dialing areas serviced by a single local telephone company. Publisher: Cisco Press
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240 interface.

In routing or transport terminology, a network connection or a port.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Interior Gateway Protocol (IGP). Internet the protocol to exchange routing informationEthernet, within anand autonomous system. Discover latestused developments in metro networking, MPLS services and Examples of common Internet IGPs include IGRP, OSPF, and RIP. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

L
L2TPv3. An L2 tunneling protocol that allows the tunneling of Ethernet packets over an L3 IP network.
Table of Contents Index

• •

Metro Ethernet BySam block. label Halabi

Publisher: Cisco Press

A block of MPLS labels exchanged between two MPLS routers.
ISBN: 1-58705-096-X

Pub Date: October 01, 2003

240 LabelPages: Distribution Protocol (LDP).

A standard protocol between MPLS-enabled routers to negotiate the labels (addresses) used to forward packets. The Cisco proprietary version of this protocol is the Tag Distribution Protocol (TDP). The definitive guide to Enterprise and Carrier Metro Ethernet applications. labelDiscover switch router (LSR). the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Forwards packets in an MPLS network by looking only at the fixed-length label. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts labelGain switched path (LSP). of industry innovator and best-selling Cisco Press author, Sam from the experience Halabi, author of Internet Routing Architectures A path that MPLS packets traverse between two edge LSRs. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has lambda-switch capable (LSC) interfaces. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded Interfaces that can forward data based on the wavelength on which it was received. This is by enterprise customers and consumers. This is not only a technology shift, but also a shift in the typical of optical cross-connects that switch traffic on the wavelength level. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Layer 2-switch capable (L2SC) interfaces. view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Interfaces that can recognize L2 cell or frame boundaries and can forward data based on L2 headers. This is typical of interfaces on ATM switches, Frame Relay switches, and L2 Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers Ethernet switches. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Link Aggregation Control Protocol (LACP). A protocol that allows multiple Ethernet links to be bundled in a larger pipe.

link bundling. Aggregating multiple links into a bigger pipe.

Link Management Protocol (LMP).
• • Table of Contents Establishes and maintains control channel connectivity between neighbors. LMP also Index enables neighbor discovery, which allows neighbors to identify connected devices, obtain Metro Ethernet UNI connectivity information, and identify and verify port-level connections, network-level and corresponding operational states for every link. BySam addresses, Halabi
Publisher: Cisco Press Pub Date: October 01, 2003 LSP tunnel. ISBN: 1-58705-096-X Pages: A configured 240

connection between two routers that uses MPLS to carry the packets.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

M
maximum transmission unit (MTU). Maximum packet size, in bytes, that a particular interface can handle.
• •
BySam Halabi

Table of Contents Index

Metro Ethernet Media Access

Control (MAC) address.

Standardized data link layer address that is required for every port or device that connects to a LAN. Other devices in the network use these addresses to locate specific ports in the Publisher: Cisco Press network and to create and update routing tables and data structures. MAC addresses are 6 Pub Date: October 01, 2003 bytes long and are controlled by the IEEE.
ISBN: 1-58705-096-X Pages: 240

metropolitan area network (MAN). Network that spans a defined metropolitan or regional area; smaller than a WAN but larger than a LAN. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and multidwelling what they units can do(MDUs). for your organization Buildings that multiple housing such as apartment complexes university Learn from the contain easy-to-read format that units, enables networking professionals of and all levels to dormitories. understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures multiple service operator (MSO). Metro networks will emerge as the next area of growth for the networking industry and will Cable service provider that also provides other services, such asand data and voice customers. telephony. represent a major shift in how data services are offered to businesses residential The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded multiplexing. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Scheme that allows multiple logical signals to be transmitted simultaneously across a offer enhanced data services. single physical channel. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. multipoint-to-multipoint (MP2MP). Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers An any-to-any connection between end systems. to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Multiprotocol Label Switching (MPLS). Switching method that forwards IP traffic using a label. This label instructs the routers and switches in the network where to forward the packets based on pre-established IP routing information.

multitenant units (MTUs). Multitenant building offices that are recipients of broadband services by a BLEC.

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

N
Network Management System (NMS). System responsible for managing at least part of a network. An NMS is generally a reasonably powerful and well-equipped computer, such as an engineering workstation. Table of Contents NMSs communicate with agents to help keep track of network statistics and resources.
Index

• •

Metro Ethernet BySam Halabi

Network-to-Network Interface (NNI).
Publisher: Cisco Press Pub Date: October 01, 2003

A specification of the interface between a backbone system and another backbone system. For example, the specification of an optical interface that connects two optical switches in ISBN: 1-58705-096-X the carrier network.

Pages: 240

Notify message. A message used RSVP-TE to notify other nodes of certain failures. The definitive guide to by Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

O
OAM&P. Operations, administration, maintenance, and provisioning. Provides the facilities and personnel required to manage a network.
Table of Contents Index

• •

Metro Ethernet BySam Halabi optical cross-connect (OXC).

Publisher: Cisco Press

A network device that switches high-speed optical signals.
ISBN: 1-58705-096-X

Pub Date: October 01, 2003

Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

P
packet multiplexing. Data packets coming in from different locations and being multiplexed over the same output wire.
Table of Contents Index

• •

Metro Ethernet BySam Halabi packet-switch capable (PSC).

Publisher: Cisco Press

Systems such as IP/MPLS routers that can switch data packets.
ISBN: 1-58705-096-X

Pub Date: October 01, 2003

Pages: 240 capable (PSC) interfaces. Packet-switch

Interfaces that can recognize packet boundaries and can forward data based on packet headers. This is typical of interfaces on routers and Layer 3 Ethernet switches. The definitive guide to Enterprise and Carrier Metro Ethernet applications. packet switching. Discover the latest developments in metro networking, Ethernet, and MPLS services and The ability to forward packets in the network based on packet headers or fixed labels. what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts peak information rate (PIR). Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Specifies the maximum rate above the CIR at which traffic is allowed into the network and Halabi, author of Internet Routing Architectures may get delivered if the network is not congested. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has point of local repair (PLR). been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded The router at which a failed LSP can be locally rerouted. by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. point-to-point (P2P). Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which based on TDM technology, and discusses the A one-to-one connection between twois end systems. drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book provider (P) device. then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area router networks (VLAN), virtual private LAN services (VPLS), Normally, a core IP/MPLS that offers a second level of aggregation for the traffic provider engineering, and MPLS and Generalized MPLS (GMPLS). edge devices.

provider edge (PE) device.

A provider-owned device that offers the first level of aggregation for the different customer edge (CE) devices.

pseudowire (PW).
• •
Metro Ethernet BySam Halabi

A representation of packet-leased line, or a virtual circuit between two nodes.
Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

Q
Q-in-Q. An Ethernet encapsulation technique that allows Ethernet packets that already have an 802.1Q VLAN tag to be 802.1Q VLAN tagged again.
Table of Contents Index

• •

Metro Ethernet BySam Halabi

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

R
Record Route Object (RRO). A field that indicates the path that traffic takes when forwarded.
• •
BySam Halabi

Table of Contents Index

Metro Ethernet regional Bell

operating company (RBOC).

Regional telephone company formed by the breakup of AT&T.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Resilient Packet Ring (RPR). Pages: 240

A Media Access Control standard protocol that adds resiliency and protection to packet networks deployed in a ring topology.

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Resource Reservation Protocol (RSVP). Protocol the thatlatest supports the reservation of resources across an IP network. Applications Discover developments in metro networking, Ethernet, and MPLS services and running on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, what they can do for your organization jitter, maximum burst, and so on) of the packet streams they want to receive. Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts RSVP-TE. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures A protocol that extends RSVP to support traffic engineering over an IP/MPLS network. Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

S
Shared Explicit (SE). Reservation style that allows a receiver to explicitly select a reservation for a group of senders, rather than one reservation per sender, such as in the FF style. Only a single Table of Contents reservation is shared between all senders listed in the particular group.
Index

• •

Metro Ethernet BySam Halabi

shared risk link group (SRLG).
Publisher: Cisco Press Pub Date: October 01, 2003

A grouping that indicates similar risk characteristics for a set of elements. A set of fibers, for example, that share the same conduit belong to the same SRLG, because if the conduit ISBN: 1-58705-096-X is cut, all fibers will fail.

Pages: 240

shortest path first (SPF) algorithm. Routing guide algorithm that iterates length of path to determine a shortest-path spanning The definitive to Enterprise and on Carrier Metro Ethernet applications. tree. Commonly used in link-state routing algorithms. Sometimes called Dijkstra's algorithm. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization SONET/SDH terminal multiplexer (TM). Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts A device installed at an endpoint on a transmission line that multiplexes multiple transmission such as into a SONET/SDH network. Gain from the lines, experience of DS1s/DS3s, industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will spanning tree. represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has Loop-free subset of a network topology. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to Synchronous Hierarchy (SDH). offer enhanced Digital data services. standard for Cisco delivering data over optical fiber. SDH useddata in Europe. Metro A Ethernet from Press looks at the deployment of is metro services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Synchronous Network (SONET). Metro Ethernet Optical discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book A standard for delivering data over optical fiber. SONET is used in North America and parts then examines current and emerging trends, and delves into the role of virtual private networks of Asia. (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS). Synchronous Payload Envelope (SPE). The payload-carrying portion of the STS signal in SONET. The SPE is used to transport a tributary signal across the synchronous network. In most cases, this signal is assembled at

the point of entry to the synchronous network and is disassembled at the point of exit from the synchronous network. Within the synchronous network, the SPE is passed on intact between network elements on its route through the network.

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

T
time-division multiplexing (TDM). Technique in which information from multiple channels can be allocated bandwidth on a single wire based on preassigned time slots. Bandwidth is allocated to each channel Table of Contents regardless of whether the station has data to transmit.
Index

• •

Metro Ethernet BySam Halabi

time-division multiplexing (TDM) interfaces.
Publisher: Cisco Press Pub Date: October 01, 2003

Interfaces that can recognize time slots and can forward data based on the data's time slot in a repeating cycle. This is typical of interfaces on digital cross-connects, SONET ADMs, ISBN: 1-58705-096-X and SONET cross-connects.

Pages: 240

Time To Live (TTL). A mechanism loops in IP networks. The TTL field gets decremented every time a The definitive guide to to prevent Enterprise and Carrier Metro Ethernet applications. packet traverses a router. When TTL reaches 0, the packet can no longer be forwarded. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization traffic engineered (TE) link. Learn from the easy-to-read format that enables networking professionals of all levels to A link that is set up to divert the traffic over a path different than what is calculated by understand the concepts Interior Gateway Protocols. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures traffic engineering (TE). as the next area of growth for the networking industry and will Metro networks will emerge represent a major shift in how data services are offered to businesses and residential customers. Techniques and processes that cause routed traffic to travel through the network on ait path The metro has always been a challenging environment for delivering data services because has other than the one that would have been chosen if standard routing methods were used. been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to traffic engineering (TE) tunnel. offer enhanced data services. label-switched tunnel that is used for deployment traffic engineering. Such tunnel is set up through Metro A Ethernet from Cisco Press looks at the of metro dataa services from a holistic means other than normal L3 routing; it is used to direct traffic over a path different from view. It describes the current metro, which is based on TDM technology, and discusses the the one that L3 routing could cause the tunnel to take. drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book traffic trunk. current and emerging trends, and delves into the role of virtual private networks then examines (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Physical and logical connection between two switches across which network traffic travels. engineering, and MPLS and Generalized MPLS (GMPLS). A backbone is composed of a number of trunks.

Transparent LAN Service (TLS).

A service that extends the LAN over the MAN and WAN.

trunk. Physical and logical connection between two switches across which network traffic travels. A backbone is composed of a number of trunks.
Table of Contents Index

• •

Metro Ethernet

tunnel. BySam Halabi
Publisher: Cisco Press

A connection between two end systems that allows the encapsulation of packets within it.

Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

U
unidirectional path switched ring (UPSR). Path-switched SONET rings that employ redundant, fiber-optic transmission facilities in a pair configuration. One fiber transmits in one direction, and the backup fiber transmits in Table of Contents the other. If the primary ring fails, the backup takes over.
Index

• •

Metro Ethernet BySam Halabi

unnumbered link.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

A link that does not have an IP address assigned to it.

User-to-Network Interface (UNI). A specification of the interface between an end system and a backbone system. An example is the specification of an Ethernet interface that connects a switch at the customer site and guide a router at the provider site. Metro Ethernet applications. The definitive to Enterprise and Carrier Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

V
virtual circuit (VC). Logical circuit created to ensure reliable communication between two network devices. A virtual circuit is defined by a VPI/VCI pair, and can be either permanent (PVC) or switched Table of Contents (SVC).
Index

• •

Metro Ethernet BySam Halabi

Virtual Container.
Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X

An SDH signal that transports payloads that are smaller than an STM-0 (48,384 kbps) payload. VC is part of the SDH hierarchy.

Pages: 240

virtual LAN (VLAN). Group of devices on one or more LANs that are configured (using management software) so that they can as if theyMetro were Ethernet attached applications. to the same wire, when in fact they The definitive guide to communicate Enterprise and Carrier are located on a number of different LAN segments. Because VLANs are based on logical instead of physical connections, they are extremely flexible. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Virtual Private Service (VPLS). Learn from LAN the easy-to-read format that enables networking professionals of all levels to understand the concepts A service that extends the notion of a switched Ethernet LAN over an IP/MPLS network. Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures virtual router forwarding Metro networks will emerge (VRF). as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. A VPN routing/forwarding instance. environment A VRF consists ofdelivering an IP routing a derived The metro has always been a challenging for datatable, services because it has forwarding table, a set of interfaces that use the forwarding table, and a set of will rules and to been built to handle the stringent reliability and availability needs for voice. Carriers have routing protocols that determine what goes into the forwarding table. In general, a VRF go through fundamental shifts to equip the metro for next-generation data services demanded includescustomers the routing information that defines customer VPN site that but is attached to ain PE by enterprise and consumers. This is notaonly a technology shift, also a shift the router. operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Virtual view. It Tributary. describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. A SONET signal that transports payloads that are smaller than an STS-1 (44,736 kbps) is part of the SONETof hierarchy. Metro payload. Ethernet VT discusses the adoption metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

W
waveband. A set of contiguous wavelengths that can be switched together as a unit.
• •
BySam Halabi

Table of Contents Index

Metro Ethernet wavelength-division

multiplexing (WDM).

Optical technology whereby multiple optical wavelengths can share the same transmission fiber. The spectrum occupied by each channel must be adequately separated from the Publisher: Cisco Press others.
Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

Wildcard Filter (WF). Reservation style in which a single shared reservation is used for all senders to a session. The total reservation on a link remains the same regardless of the number of senders. The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X]

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] access control EOS with packet multiplexing Ethernet 2nd to building risers add • operation

Table of Contents

add/drop multiplexers (ADMs) • Index addresses Metro Ethernet MAC BySam Halabi learning 2nd 3rd switching 2nd Publisher: Cisco Press VPN-IPv4 Pub Date: October 01, 2003 adjacency FA ADM ISBN: 1-58705-096-X Pages: 240 EOS function inside provisioning administrative status information ADMs (add/drop multiplexers) aggregation trunks into tunnels AIS (Alarm Indicator Signal) Discover the latest Alarm Indicator Signal (AIS) what they can do algorithms pathLearn computation from link protection types understand the all-to-one Gain bundling from architecture

administration

The definitive guide to Enterprise and Carrier Metro Ethernet applications. developments in metro networking, Ethernet, and MPLS services and for your organization

the easy-to-read format that enables networking professionals of all levels to concepts

all-Ethernet networks, building

the experience of industry innovator and best-selling Cisco Press author, Sam

arbitrary Halabi, contiguous author concatenation of Internet [See also Routing concatenation] Architectures

Metro networks will emerge as the next area of growth for the networking industry and will GMPLS 2nd represent a major shift in how data services are offered to businesses and residential customers. interfaces 2nd The need metro for has 2nd always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to SONET/SDH 2nd go through Asian markets fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the attributes operational and business model that will allow the incumbent carriers to transform the metro to MEF 2nd offerexample enhanced data services. of 2nd Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic site of origin view. It describes the current metro, which is based on TDM technology, and discusses the traffic drivers and challenges carriers will face in transforming the metro to address data services. parameters Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers augmented model [See also siganling] to the delivery of metro data services. With a changing mix of transport technologies, the book autodiscovery then examines current and emerging trends, and delves into the role of virtual private networks availability (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic avoiding engineering, and MPLS and Generalized MPLS (GMPLS). loops
traffic trunks routes

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] backbones L3VPNs delivering IP over 2nd scaling traffic

•

forwarding Table of Contents

backdoor loops Index • backward trunks Metro Ethernet bandwidth BySam Halabi encoding Ethernet Publisher: Cisco Press requirements Pub Date: October 01, 2003 RPR 2nd VCAT ISBN: 2nd 1-58705-096-X benefitsPages: of link 240 bundling BER (bit error rate) BGP signaling bidirectional LSPs billing

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
binding labels 2nd bit error rate (BER)the Discover block offset breadth of services Learn from breaking understand loops broadcast Gain broadcast Halabi, framesauthor broadcast storms

latest developments in metro networking, Ethernet, and MPLS services and

BLECs (Building Local Exchange Carriers) what they can do for your organization

the easy-to-read format that enables networking professionals of all levels to the concepts

from the experience of industry innovator and best-selling Cisco Press author, Sam of Internet Routing Architectures

Metro networks will emerge building all-Ethernt data networks

as the next area of growth for the networking industry and will services are offered to businesses and residential customers. The metro always been a challenging environment for delivering data services because it has building risers,has access to been built to handle the stringent reliability and availability needs for voice. Carriers will have to bundling golinks through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the Bundling service attribute operational bypass tunnels and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. represent major shift in(BLECs) how data Building Locala Exchange Carriers Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] cable modem termination systems (CMTSs) capabilties interface switching descriptors 2nd 3rd carriers, metro Ethernet CBS (Committed Burst Size) CCAMP (Common Control and Measurement Plane) Working Group • Table of Contents CE • (customer edge) Index central office (CO) Metro Ethernet centralized provisioning BySam Halabi TDM networks 2nd centralized switching Publisher: Cisco Press EOS with Pub Date: October 01, 2003 channels control ISBN: 1-58705-096-X separating Pages: 240 data separating fault handling 2nd CIR (Committed Information Rate) circuits

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
provisioning class of service (CoS) parameters CMTSs Discover (cable modem termination systems) the latest developments CO (central office) what they Committed Burst Size (CBS) Committed Information Rate (CIR) Learn from the easy-to-read comparisons Frame Gain Relay from 2nd component links GMPLS/MPLS Halabi, 2nd author

in metro networking, Ethernet, and MPLS services and can do for your organization format that enables networking professionals of all levels to

Common Control and Measurement Plane (CCAMP) Working Group understand the concepts

the experience of industry innovator and best-selling Cisco Press author, Sam of Internet Routing Architectures

Metro networks components

will emerge as the next area of growth for the networking industry and will represent VPN 2nd a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has computation been built to handle the stringent reliability and availability needs for voice. Carriers will have to paths go through fundamental shifts to equip the metro for next-generation data services demanded link protection types by enterprise customers and consumers. This is not only a technology shift, but also a shift in the concatenation operational and business model that will allow the incumbent carriers to transform the metro to SONET/SDH 2nd offer enhanced data services. VCAT 2nd
configuration

Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic hub-and-spoke view. It describes Gigabit Ethernet the current metro, which is based on TDM technology, and discusses the drivers L2PE and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers PW to the delivery of metro data services. With a changing mix of transport technologies, the book congestion then examines current and emerging trends, and delves into the role of virtual private networks TE (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic connections engineering, and MPLS and Generalized MPLS (GMPLS). EVC
last-mile metro [See metro] mulitpoint VPN components 2nd PE

connectivity LCASconstrained-based routing LDP (CR-LDP) constraint-based routing 2nd contiguous standard SONET concatenation [See also concatenation, SONET/SDH] control channels fault handling separating

• •

CoS (class of service) parameters

Table of Contents Index

costs Metro Ethernet overbuilding networks By Sam Halabi premises equipment) CPE (customer CR-LDP (constrained-based routing LDP) cross-connect Publisher:(XC) Cisco Press customer edge October (CE) Pub Date: 01, 2003 customer premises equipment (CPE) ISBN: 1-58705-096-X customers Pages: 240 restrictions to number of

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] data channels separating data equipment EOS interfaces in Data Packet Transport (DPT) data-link connection identifier (DLCI) • Table of Contents Decoupled Transparent • Index LAN Service (DTLS) delay Metro Ethernet delivering BySam Halabi L3VPNs over IP 2nd deployment Publisher: Cisco Press Ethernet L2 services Pub Date: 2nd October incumbents 3rd 01, 2003 international ISBN: 1-58705-096-X 2nd legacy Pages: 240 interworking with 2nd metro 2nd RPR services RPR 2nd

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
descriptors interface switching capability 2nd 3rd detour Discover LSPs deviceswhat CE non-bridging Learn from as spokes understand P PE Diffserv Halabi, codepoints author (DSCPs) of Digital Wrapper (DW)

the latest developments in metro networking, Ethernet, and MPLS services and they can do for your organization the easy-to-read format that enables networking professionals of all levels to the concepts

Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Internet Routing Architectures

Metro networks discovery

will emerge as the next area of growth for the networking industry and will represent resource a major shift in how data services are offered to businesses and residential customers. The topologies metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to DLCI (data-link connection identifier) go through fundamental shifts to equip the metro for next-generation data services demanded documentation byMEF enterprise [See MEF]customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to DPT (Data Packet Transport) offer enhanced data services. drop operation
DSCPs (Diffserv codepoints)

Metro Ethernet from Cisco Press looks DTLS (Decoupled Transparent LAN Service) view. It describes the dual-homed MTU devices

at the deployment of metro data services from a holistic current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. DW (Digital Wrapper)
dynamic provisioning model 2nd

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] E-LAN (Ethernet LAN Service) early service providers of metro Ethernet 2nd EBGP (External BGP) edge,core ELS (Ethernet Line Service) emulation •

Table of Contents Index

• links
encapsulation Metro Ethernet Ethernet BySam Halabi GRE

VPLS Publisher: Cisco Press encoding Pub Date: October 01, 2003 bandwidth LSP types ISBN: 1-58705-096-X end-to-end repair method Pages: 240 Enterprise Systems Connection (ESCON) EOS interfaces packet mulitplexing at access packet switching 2nd

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
transport services 2nd EOS functions ERO (EXPLICIT_ROUTE Discover the object) latest ERO (EXPLICIT_ROUTE) object 2nd what they can do for your ESCON (Enterprise Systems Connection) establishing trunks, RSVP-TE 2nd Learn from the easy-to-read Ethernet 2nd understand access 2nd early Gain service from providers the of experience 2nd L2VPN services 2nd Gigabit Halabi, Ethernet author [See Gigabit of Internet Ethernet] Routing

developments in metro networking, Ethernet, and MPLS services and organization format that enables networking professionals of all levels to

the concepts of industry innovator and best-selling Cisco Press author, Sam Architectures

Metro networks will emerge as the next area of growth for the networking industry and will MEF 2nd represent major shift in how data services are offered to businesses and residential customers. examplea of 2nd The metro has always been a challenging environment for delivering data services because it has over SONET/SDH 2nd been built to handle the stringent reliability and availability needs for voice. Carriers will have to services go through fundamental over IP/MPLS networks 2ndshifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the over MPLS 2nd operational PW 2nd and business model that will allow the incumbent carriers to transform the metro to offerVPLS enhanced data services. 2nd Metro Ethernet from Cisco Ethernet LAN Service (E-LAN) view. It describes the Ethernet Line Service (ELS) Press looks at the deployment of metro data services from a holistic current metro, which is based on TDM technology, and discusses the driversphysical and challenges carriers will face in transforming the metro to address data services. Ethernet interface attribute
Ethernet Virtual Connection (EVC) transport 2nd

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers European markets 2nd to the delivery of metro data services. With a changing mix of transport technologies, the book EVC (Ethernet Virtual Connection) then examines current and emerging trends, and delves into the role of virtual private networks existing legacy TDM infrastructure (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic expanding capacity engineering, and MPLS and Generalized MPLS (GMPLS). explicit label control
explicit paths, establishing EXPLICIT_ROUTE object (ERO) 2nd 3rd extensions RSVP External BGP (EBGP)

extranets

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] FA (forwarding adjacency) facility backups fairness RPR fast provisioning fast • reroute

Table of Contents Index

• MPLS 2nd

fault handling 2nd Metro Ethernet fault management BySam Halabi FCS (frame check sequence) FF (Fixed Filter) Publisher: Cisco Press Base) FIB (Forwarding Information Date: October 01, 2003 fiber Pub connectivity (FICON) fiber-switch ISBN: capable 1-58705-096-X (FSC) interfaces Pages: 240 fibers SRLG FICON (fiber connectivity) fields TLV

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
filters resource reservation styles first mile Discover Fixed Filter what

the latest developments in metro networking, Ethernet, and MPLS services and they can do for your organization from the easy-to-read format that enables networking professionals of all levels to the concepts

flexibility of service flooding Learn formatting frames Gain SONET/SDH Halabi, author loop-free topologies FLOW_SPEC object understand

from the experience of industry innovator and best-selling Cisco Press author, Sam of Internet Routing Architectures

Metro operation networks forward represent a forward trunks

will emerge as the next area of growth for the networking industry and will major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has forwarding been built to handle the stringent reliability and availability needs for voice. Carriers will have to packets gotables through fundamental shifts to equip the metro for next-generation data services demanded bytraffic enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to forwarding adjacency (FA) offer enhanced data services. Forwarding Information Base (FIB)
forwarding paths, establishing

Metro Ethernet from Cisco frame check sequence (FCS) view.Relay It describes Frame
VPNs

Press looks at the deployment of metro data services from a holistic the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. comparisons 2nd Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers frames to service the delivery of metro data services. With a changing mix of transport technologies, the book frame delivery attribute then examines current and emerging trends, and delves into the role of virtual private networks SONET/SDH (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic formats engineering, and MPLS and Generalized MPLS (GMPLS). FSC (fiber-switch capable)
interfaces full mesh loops avioding LSPs

functions EOS NSP Q-in-Q

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] G-PID (Generalized Payload Identifier) GARP (Generic Attribute Registration Protocol) generalized labels 2nd Generalized MPLS [See GMPLS] Generalized Payload Identifier (G-PID) Generic AttributeTable Registration Protocol (GARP) • of Contents Generic Framing Index Protocol (GFP) • generic path selection Metro Ethernet generic routing encapsulation (GRE) tunnels BySam Halabi geography, variations of deployment GFP (Generic Framing Protocol) Publisher: Cisco Press Gigabit Ethernet Pub Date: October 01, 2003 hub-and-spoke configuration rings ISBN: 1-58705-096-X global access control Pages: 240 GMPLS inclusion of technology-specific parameters 2nd interfaces 2nd LMP MPLS

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
comparing 2nd protection 2nd restoration 2nd Discover need for 2nd granularity Learn bandwidth understand GMPLS what (Generalized 2nd they MPLS) can do for

the latest developments in metro networking, Ethernet, and MPLS services and your organization

from the easy-to-read format that enables networking professionals of all levels to the concepts of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

GRE (generic routing encapsultion) tunnels greenfield Gain value from proposition the experience 2nd groups Halabi, SRLG

Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] hierarchies LSP 2nd LSPs VPLS scaling hops •

Table of Contents Index

• loose

strict Metro Ethernet hub-and-spoke configuration BySam Halabi Gigabit Ethernet Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] IBGP (Internal BGP) identification interfaces PW IGP

• metrics

Table of Contents

ILEC (incumbentIndex local exchange carrier) • implementation Metro Ethernet RSVP BySam Halabi inclusion of technology-specific parameters 2nd incumbent local exchange carrier (ILEC) Publisher: Cisco Press incumbents Pub Date: 2nd October deployment 3rd 01, 2003 infrastructure ISBN: 1-58705-096-X signaling models Pages: 240 2nd SONET/SDH Ethernet over 2nd infrastructureLexisting legacy TDM installing physical ports EOS Frame Relay Discover FSC what GMPLS 2nd identification Learn from L2 L2SC LSC Gain PSC NNI Halabi,

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
interfaces

the latest developments in metro networking, Ethernet, and MPLS services and they can do for your organization

the easy-to-read format that enables networking professionals of all levels to understand the concepts from the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

Metro networks switching 2nd 3rd will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. TDM The metro has always been a challenging environment for delivering data services because it has UNI 2nd been built to handle the stringent reliability and availability needs for voice. Carriers will have to Internal BGP (IBGP) go through fundamental shifts to equip the metro for next-generation data services demanded international deployment 2nd by enterprise customers and 2nd consumers. This is not only a technology shift, but also a shift in the interworking with legacy deployments operational and business model that will allow the incumbent carriers to transform the metro to intranets offer enhanced IP/MPLS networks data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic MPLS 2nd view. It2nd describes the current metro, which is based on TDM technology, and discusses the PW drivers and VPLS 2nd challenges carriers will face in transforming the metro to address data services.
IPv4 Ethernet services over 2nd

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers VPN-IPv4 addresses to the delivery of metro data services. With a changing mix of transport technologies, the book IS-IS Traffic Engineering (IS-IS-TE) then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] jitter

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] L2 backbones scaling interfaces L2PE

• configuring • labels

Table of Contents Index

L2SC (Layer 2 switch capable) Metro Ethernet interfaces BySam Halabi L2TP control connection endpoints (LCCEs) L2VPN BGP model 2nd Publisher: L2VPN services Cisco 2nd Press Pub Date: October 01, 2003 L3VPNs IP ISBN: 1-58705-096-X delivering over 2nd Pages: 240 Label Distribution Protocol (LDP) label switched path (LSP) label switched paths (LSPs) label switched routers (LSRs) LABEL_REQUEST object 2nd labels binding 2nd explicit control Discover L2PE optimizing Learn sets suggested Gain 2nd from switching Halabi, GMPLS 2nd ranges understand generalized 2nd what they

The definitive guide to Enterprise and Carrier Metro Ethernet applications. the latest developments in metro networking, Ethernet, and MPLS services and can do for your organization

from the easy-to-read format that enables networking professionals of all levels to the concepts the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

Metro networks will emerge as the next area of growth for the networking industry and will nonpackets represent a major shift in how data services are offered to businesses and residential customers. troubleshooting The metro has always been a challenging environment for delivering data services because it has WAN been built to handle the Protocol) stringent reliability and availability needs for voice. Carriers will have to LACP (Link Aggregation Control go through capable fundamental shifts to equip the metro for next-generation data services demanded lambda-switch (LSC) byinterfaces enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to lambdas offer enhanced data services. SRLG
LAN

Metro from Cisco Press looks at the deployment of metro data services from a holistic VPLS Ethernet 2nd view. It area describes the current metro, which is based on TDM technology, and discusses the LAN (local network) drivers and challenges carriers will face in transforming the metro to address data services. resources
large enterprises (LEs)

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers last mile to the delivery of metro data services. With a changing mix of transport technologies, the book last-mile then examines current and emerging trends, and delves into the role of virtual private networks connectivity (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Layer 2 switch capable (L2SC) engineering, and MPLS and Generalized MPLS (GMPLS). interfaces
Layer Control Processing packets layers SONET/SDH 2nd LCAS (Link Capacity Adjustment Scheme) LCCEs (L2TP control connection endpoints)

LDP BGP signaling CR-LDP directly connected PEs LDP (Label Distribution Protocol) learning MAC addresses

• •

qualified/unqualified

Table of Contents Index

learning, MAC 2nd Metro Ethernet legacy deployments, interworking with 2nd By Sam Halabi LEs (large enterprises) line overhead (LOH) Link Publisher: Aggregation Control Protocol (LACP) Cisco Press Link Pub Capacity Adjustment Scheme Date: October 01, 2003 (LCAS) Link Management Protocol (LMP) ISBN: 1-58705-096-X links Pages: 240 bundling emulating GMPLS protection/restoration 2nd protection types

The definitive guide to Enterprise and Carrier Metro Ethernet applications. unnumbered
LMP (Link Management Protocol) local access control resources local area network (LAN) local link identifiers local switching EOS with 2nd PE

Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

logical Gain separation from LOH (line overhead)

LOL (loss of light) Metro networks

will emerge as the next area of growth for the networking industry and will in how data services are offered to businesses and residential customers. loops The metro has always been a challenging environment for delivering data services because it has avoiding been built to handle the stringent reliability and availability needs for voice. Carriers will have to gobackdoor through fundamental shifts to equip the metro for next-generation data services demanded loose hops by enterprise customers and consumers. This is not only a technology shift, but also a shift in the loss operational and business model that will allow the incumbent carriers to transform the metro to loss of enhanced light (LOL) data services. offer
loop-free topologies, creating represent a major shift LSC (lambda-switch capable) interfaces Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic LSP view. It describes the current metro, which is based on TDM technology, and discusses the encoding types drivers and challenges carriers will face in transforming the metro to address data services. full mesh

Metro Ethernet hierarchies 2nd discusses the adoption of metro Ethernet services and how that has led carriers to RSVP the delivery of metro data services. With a changing mix of transport technologies, the book tunnels 2nd then examines current and emerging trends, and delves into the role of virtual private networks tunnels (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic LSP (label switched path) engineering, and MPLS and Generalized MPLS (GMPLS). LSPs
bidirectional heriarchies traffic trunks comparing to LSPs (label switched paths)

LSRs GMPLS interfaces 2nd LSRs (label switched routers)

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] MAC addresses learning learning 2nd switching 2nd MAC (Media Access Control) • Table of Contents

• RPR
management Metro Ethernet fault BySam Halabi LMP

Index

networks Publisher: Cisco Press NFS Pub Date: October 01, 2003 Maximum Burst Size (MBS) Maximum ISBN: Transmit 1-58705-096-X Unit (MTU) MBS (Maximum Burst Size) Pages: 240 MDUs (multidwelling units) Media Access Control (MAC) RPR MEF (Metro Ethernet Forum) 2nd example of 2nd Notify PATH 2nd Discover RESV what metrics IGP Learn metro

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
messages

the latest developments in metro networking, Ethernet, and MPLS services and they can do for your organization

from the easy-to-read format that enables networking professionals of all levels to understand the concepts the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

data view of 2nd deployment Gain from 2nd Ethernet Halabi, 2nd

early service providers of 2nd

Metro networks will emerge as the next area of growth for the networking industry and will MEF 2nd represent major shift in how data services are offered to businesses and residential customers. examplea of 2nd The metro has always been a challenging environment for delivering data services because it has services 2nd beenEthernet built to handle the stringent reliability and availability needs for voice. Carriers will have to Metro Forum [See MEF] go through fundamental shifts to equip the metro for next-generation data services demanded migration byEOS enterprise customers as transport services 2ndand consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to modification offer enhanced data services. routing 2nd Metro Ethernet monitoring from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the services drivers and challenges MP-BGP (multiprotocol BGP) carriers will face in transforming the metro to address data services.
MP2MP (multipoint-to-multipoint) signaling 2nd

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers MPLS to Ethernet the delivery of metro data services. With a changing mix of transport technologies, the book over 2nd then examines current and emerging trends, and delves into the role of virtual private networks fast reroute 2nd (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic GMPLS engineering, and MPLS and Generalized MPLS (GMPLS). comparing 2nd
TE 2nd MPLS L3VPN 2nd MPLS L3VPNs MSOs (multiple service operators) MTU

dual-homed devices MTU (Maximum Transmit Unit) MTU-s 2nd MTUs (multitenant units) mulitcast mulitple fibers SRLG mulitplexing

• •

packets at access

Table of Contents Index

multicast frames Metro Ethernet multidwelling units (MDUs) By Sam Halabi multiple lambdas SRLG multiple LSPs Cisco Press Publisher: nesting 2nd October 01, 2003 Pub Date: multiple ISBN: service operators (MSOs) 1-58705-096-X multiple services Pages: 240 multiple switching capabilities 2nd 3rd multiple T1 (nXT1) multiple TE links bundling multiplexing

The definitive guide to Enterprise and Carrier Metro Ethernet applications. WDM
multipoint connectivity multipoint-to-multipoint (MP2MP) multiprotocol BGP (MP-BGP) multitenant units (MTUs)

Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] Native Service Processing (NSP) need for GMPLS 2nd nesting multiple LSPs 2nd Network Layer Reachability Information (NLRI) Network Management System (NMS) Network-to-Network Interface (NNI) • Table of Contents networks • all-Ethernet Metro Ethernet building BySam Halabi GMPLS 2nd need for 2nd Publisher: Cisco Press IP/MPLS Pub Date: services October over 01, 2003 Ethernet 2nd over ISBN: MPLS 1-58705-096-X 2nd over VPLS 2nd Pages: 240 PW 2nd management metro [See metro] on-net OTN

Index

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
overbuilding reliability equal-cost multipath (TE) Discover the latest IGP metrics (TE) what they can routing (TE) TE 2nd Learn techniques (TE) 2nd understand the VC overlays (TE) ring Gain RPR Halabi, 2nd

developments in metro networking, Ethernet, and MPLS services and do for your organization

from the easy-to-read format that enables networking professionals of all levels to concepts

from the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

signaling models 2nd

Metro networks will emerge as the next area of growth for the networking industry and will SONET/SDH represent a major bidirectional LSPs shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has TDM been built to handle label switching 2nd the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded provisioning 2nd bytroubleshooting enterprise customers and consumers. This is not only a technology shift, but also a shift in the 2nd operational trunking 2ndand business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. WAN Metro WDM Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the label switching drivers and Layer challenges carriers will face in transforming the metro to address data services. NLRI (Network Reachability Information)
NMS (Network Management System) labels

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers NNI (Network-to-Network Interface) to the delivery of metro data services. With a changing mix of transport technologies, the book nodal fault handling then examines current and emerging trends, and delves into the role of virtual private networks node pairs (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic LMP engineering, and MPLS and Generalized MPLS (GMPLS). non-bridging devices
as spokes non-directly connected PEs non-PSC networking devices [See also OXCs] nonpacket label switching Notify messages

NSP (Native Service Processing) numbers unnumbered links nXT1 (multiple T1)

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] O4 objects ERO FLOW_SPEC LABEL_REQUEST 2nd

• RRO

Table of Contents • SENDER_TEMPLATE Index
SESSION Metro Ethernet SESSION_ATTRIBUTE BySam Halabi OC12 (12 STS-1s) OLE_LINK1 2nd 3rd 4th Publisher: Cisco Press OLE_LINK3 Pub Date: October 01, 2003 on-net networks one-to-one ISBN: backup 1-58705-096-X method Open Shortest Pages: Path 240 First for Traffic Engineering (OSPF-TE) operations packets traffic trunks optical cross-connects (OXCs) optical networks GMPLS 2nd

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
need for 2nd signaling models 2nd latest Discover the optical transport network (OTN) optimization Learn RPR 2nd labels Gain [See from also labels] the experience routing Halabi, [See also author routing] of signaling [See also signaling] bandwidth understand optical what signal-to-noise ratio (OSNR) they can do for your

developments in metro networking, Ethernet, and MPLS services and organization

from the easy-to-read format that enables networking professionals of all levels to the concepts of industry innovator and best-selling Cisco Press author, Sam Internet Routing Architectures

Metro networks will emerge as the next area of growth for the networking industry and will TE 2nd represent a major shift in how data services are offered to businesses and residential customers. equal-cost multipath The IGP metro has always been a challenging environment for delivering data services because it has metrics been built to handle the stringent reliability and availability needs for voice. Carriers will have to routing go through fundamental shifts to equip the metro for next-generation data services demanded techniques 2nd by enterprise VC overlays customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to OSNR (optical signal-to-noise ratio) offer enhanced data services. OSPF-TE (Open Shortest Path First for Traffic Engineering)
OTN (optical transport network)

Metro Ethernet from overbuilding networks

Cisco Press looks at the deployment of metro data services from a holistic metro, which is based on TDM technology, and discusses the drivers overlays and challenges carriers will face in transforming the metro to address data services. view. It describes the current overlay model [See also signaling]
VC

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers overprovisioning to the delivery of metro data services. With a changing mix of transport technologies, the book OXCs (optical cross-connects) then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P] [Q ] [R ] [S] [T] [U] [V] [W] [X] P (provider) P2P (point-to-point) packet-switch capable (PSC) interfaces packet-switched capable (PSC) packet-switched network tunnels • Table of(PSN) Contents packets • Index DPT Ethernet Metro EOS BySam Halabi as transport services 2nd switching 2nd Publisher: Cisco Press forwarding Pub Date: October 01, 2003 Layer Control Processing mulitplexing ISBN: 1-58705-096-X at access nonpackets Pages: 240 label switching operations PW RPR 2nd switching 2nd

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
parameters GMPLD inclusion of technology specific 2nd Discover the latest developments MEF what 2nd example of 2nd traffic Learn attributes understand PATH message 2nd path overhead Gain from (POH)the paths computation

in metro networking, Ethernet, and MPLS services and they can do for your organization from the easy-to-read format that enables networking professionals of all levels to the concepts

experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

Metro networks will emerge as the next area of growth for the networking industry and will link protection types represent a major shift in how data services are offered to businesses and residential customers. establishing The metro has always been a challenging environment for delivering data services because it has generic selection been LSP built to handle the stringent reliability and availability needs for voice. Carriers will have to goLSPs through fundamental shifts to equip the metro for next-generation data services demanded byRSVP-TE enterprise 2nd customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to pay as you grow model offer enhanced data services. PE Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic LDP with directly connected view. Itseparation describes the current metro, which is based on TDM technology, and discusses the logical drivers and connected challenges carriers will face in transforming the metro to address data services. non-directly
PE (provider edge) configuring

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers PE-rs 2nd to the delivery of metro data services. With a changing mix of transport technologies, the book Peak Information Rate (PIR) then examines current and emerging trends, and delves into the role of virtual private networks peer model [See also signaling] (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic penultimate hop popping engineering, and MPLS and Generalized MPLS (GMPLS). performance
parameters TE 2nd IGP metrics techniques 2nd physical ports

installing PIR (Peak Information Rate) planning provisioning POH (path overhead) point of presence (POP) point-to-point (P2P) policing attribute

• •

POP (point of presence) ports Metro Ethernet physical BySam Halabi installing trunks 2nd

Table of Contents Index

preemption attribute Publisher: Cisco Press pricing Pub Date: October 01, 2003 models ISBN: 1-58705-096-X overbuilding networks Pages: 240 services 2nd pricing models priority attribute protection GMPLS 2nd

The definitive guide to Enterprise and Carrier Metro Ethernet applications. link types
TLV fields protocols BGP GFP

signaling GMPLS 2nd IP

Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Routing Architectures

need for 2nd

delivering over Halabi,L3VPNs author of2nd Internet MAC

RPR Metro networks will emerge as the next area of growth for the networking industry and will modifying 2nd represent a major shift in how data services are offered to businesses and residential customers. RSVP The metro has always been a challenging environment for delivering data services because it has extensions been built to handle the stringent reliability and availability needs for voice. Carriers will have to implementing go through fundamental shifts to equip the metro for next-generation data services demanded bySRP enterprise customers and consumers. This is not only a technology shift, but also a shift in the STP operational and business model that will allow the incumbent carriers to transform the metro to loops data services. offerbreaking enhanced provider (P) provider edge (PE) Metro Ethernet

from Cisco Press looks at the deployment of metro data services from a holistic the current metro, which is based on TDM technology, and discusses the dynamic 2ndchallenges carriers will face in transforming the metro to address data services. drivers and
provisioning view. It describes path computation

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers TDM networks 2nd to the delivery of provisioning sevbrices metro data services. With a changing mix of transport technologies, the book then examines capable) current and emerging trends, and delves into the role of virtual private networks PSC (packet-swirch (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic interfaces engineering, and MPLS PSC (packet-switched capable) and Generalized MPLS (GMPLS).
PSN (packet-switched network) tunnels PW (pseudowire) 2nd 3rd 4th

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q] [R ] [S] [T] [U] [V] [W] [X] Q-in-Q function qualified learning

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] ranges labels raw mode RD (Route Distinguisher) RD (route distinguisher) reach of servicesTable of Contents • RECORD-ROUTE object (RRO) • Index RECORD_ROUTE Metro Ethernet object (RRO) reducing TDM bandwidth 2nd BySam Halabi reference models VPLS Publisher: Cisco Press regulations Pub Date: October 01, 2003 incumbents reliability ISBN: 2nd 1-58705-096-X reliablity Pages: 240 TE 2nd equal-cost multipath IGP metrics routing techniques 2nd VC overlays

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
remote link identifiers reordering Discover frames what requirements bandwidth Learn VPLS understand resilience attribute resiliency Gain RPR Halabi,

the latest developments in metro networking, Ethernet, and MPLS services and they can do for your organization from the easy-to-read format that enables networking professionals of all levels to the concepts

from the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

resilient packet ring (RPR) 2nd

Metro networks resource attributes

will emerge as the next area of growth for the networking industry and will in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has resource reservation been built to handle the stringent reliability and availability needs for voice. Carriers will have to styles go through fundamental shifts to equip the metro for next-generation data services demanded resource reservations bystyles enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to FF offerSE enhanced data services. represent a major shift resource discovery topologies Metro Ethernet resources from Cisco Press looks at the deployment of metro data services from a holistic view. LAN It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. restoration Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers restrictions to number of customers to the delivery of metro data services. With a changing mix of transport technologies, the book RESV message then examines current and emerging trends, and delves into the role of virtual private networks retail models (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic ring steering engineering, and MPLS and Generalized MPLS (GMPLS). ring wrapping
rings Gigabit Ethernet RPR 2nd risk SRLG GMPLS 2nd WF

Route Distinguisher (RD) route distinguisher (RD) route reflectors route target (RT) routers attributes interfaces GMPLS 2nd RSVP-TE 2nd

• •

Table of Contents Index

routing Metro Ethernet constraint-based 2nd BySam Halabi CR-LDP fast reroute 2nd GMPLS Publisher: Cisco Press protection/restoration 2nd Pub Date: October 01, 2003 GRE ISBN: 1-58705-096-X LSP Pages: 240 hierarchies modifying 2nd TE RPR (resilient packet ring) 2nd RRO (RECORD-ROUTE) object

The definitive guide to Enterprise and Carrier Metro Ethernet applications. RRO (RECORD_ROUTE) object
RSVP extensions implmenting RSVP-TE 2nd

LSP tunnels 2nd RT (route target)

Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] scalability 2nd bandwidth scaling backbones VPLS SDH •

Table of Contents • architecture 2nd Index
concatenation Metro Ethernet 2nd frame formats BySam Halabi SDL (Simple Data Link) SE (Shared Explicit) Publisher: Cisco Press SE (Shared explicit) Pub Date: October 2003 section overhead (SOH)01, 2nd security ISBN: 1-58705-096-X filters Pages: 240 SENDER_TEMPLATE object seperation control/data channels service flexibility of

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
service frame delivery attribute service multiplexing attribute serviceDiscover providers metro Ethernet 2nd what they can service, time to bring up services 2nd Learn Ethenet over Gain IP/MPLS from networks the experience 2nd over Halabi, MPLS 2nd author PW 2nd dataunderstand view of 2nd

the latest developments in metro networking, Ethernet, and MPLS services and do for your organization

from the easy-to-read format that enables networking professionals of all levels to the concepts of industry innovator and best-selling Cisco Press author, Sam of Internet Routing Architectures

Metro networks will emerge as the next area of growth for the networking industry and will VPLS 2nd represent MEF 2nd a major shift in how data services are offered to businesses and residential customers. The example metro has always been a challenging environment for delivering data services because it has of 2nd been built to handle the stringent reliability and availability needs for voice. Carriers will have to monitoring gomulitple through fundamental shifts to equip the metro for next-generation data services demanded bypricing enterprise customers and consumers. This is not only a technology shift, but also a shift in the 2nd operational provisioning and business model that will allow the incumbent carriers to transform the metro to offer data services. RPR enhanced 2nd Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic EOS 2nd view. VPN It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. components 2nd
SESSION object transport

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers SESSION_ATTRIBUTE object 2nd to the delivery of metro data services. With a changing mix of transport technologies, the book sets then examines current and emerging trends, and delves into the role of virtual private networks labels (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic Shared Explicit [See SE] engineering, and MPLS and Generalized MPLS (GMPLS). shared risk link group (SRLG)
siganling GMPLS protection/restoration 2nd signaling BGP

models 2nd modifying 2nd VPLS signals SONET/SDH concatenation 2nd Simple Data Link (SDL) site of origin

• •

small and medium-sized businesses (SMBs) small office/home office (SOHO) Metro Ethernet SMBs (small and medium-sized businesses) By Sam Halabi SOH (section overhead) 2nd SOHO (small office/home office) SONET Publisher: Cisco Press architecure Pub Date: 2nd October 01, 2003 concatenation 2nd ISBN: 1-58705-096-X frame formats Pages: 240 SONET/SDH Ethernet over 2nd SONET/SDH label switching SONET/SDH LSP SONET/SDH LSRs

Table of Contents Index

The definitive guide to Enterprise and Carrier Metro Ethernet applications. SONET/SDH networks
bidirectional LSPs Spanning Tree Protocol (STP) loops spans breaking

Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures

metro [See metro]

SPE (Synchronous Payload Envelope) 2nd special Gain reuse protocol (SRP) from the experience speed Frame Relay speed spokes Metro

networks will emerge as the next area of growth for the networking industry and will non-bridging devices as represent a major shift in how data services are offered to businesses and residential customers. SRLG (shared risk link group) been a challenging environment for delivering data services because it has The metro has always SRP (special protocol) been builtreuse to handle the stringent reliability and availability needs for voice. Carriers will have to stacking go through fundamental shifts to equip the metro for next-generation data services demanded static provisioning customers and consumers. This is not only a technology shift, but also a shift in the by enterprise TDM networks 2ndbusiness model that will allow the incumbent carriers to transform the metro to operational and steering, ring offer enhanced data services.
STP (Spanning Tree Protocol) loops Ethernet from Cisco Press looks at the deployment of metro data services from a holistic Metro breaking view. It describes the current metro, which is based on TDM technology, and discusses the strict hops drivers and challenges carriers will face in transforming the metro to address data services. STS-1 (50 Mbps)

Metro styles Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to resource the delivery of metro data With a changing mix of transport technologies, the book reservation 2nd [See also services. resource reservation] then examines current and emerging trends, and delves into the role of virtual private networks subobjects 2nd (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic suggested labels 2nd engineering, and MPLS and Generalized MPLS (GMPLS). support
VC waveband switching swapping switches EOS functions inside

GMPLS 2nd need for 2nd LMP switching 2nd interfaces 2nd 3rd labels GMPLS 2nd nonpackets LSP

• •

Table of Contents Index

packets Metro Ethernet EOS 2nd BySam typesHalabi waveband

Synchronous Payload Envelope (SPE) 2nd Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] tables forwarding MAC learning 2nd tagged mode tagging

• VLAN 2nd 3rdTable of Contents
target VPNs • targets Metro Ethernet RT BySam Halabi TDM existing legacy infrastructure Publisher: GMPLS 2nd Cisco Press Pub Date: October 01, 2003 need for 2nd label switching ISBN: 1-58705-096-X 2nd networks Pages: 240 provisioning 2nd TDM (time-division multiplexing) interfaces TE IS-IS-TE tunnels MPLS fast reroute Discover the 2nd latest TE (traffic engineering) 2nd what they can do equal-cost multipath IGP Learn metrics routing techniques Gain from 2nd VC overlays Halabi, MPLS 2nd understand

Index

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
OSPF-TE

developments in metro networking, Ethernet, and MPLS services and for your organization

from the easy-to-read format that enables networking professionals of all levels to the concepts the experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

time to bring up service

Metro networks will (TDM) emerge time-division multiplexing

as the next area of growth for the networking industry and will represent interfaces a major shift in how data services are offered to businesses and residential customers. The(Transparent metro has always been a challenging environment for delivering data services because it has TLS LAN Service) been built to value) handle the stringent reliability and availability needs for voice. Carriers will have to TLV (type length go through fundamental shifts to equip the metro for next-generation data services demanded TLV (type length value) fields by enterprise customers and consumers. This is not only a technology shift, but also a shift in the TOH (transport overhead) operational and business model that will allow the incumbent carriers to transform the metro to TOH (transport overload) offer enhanced data services. topologies Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic creating view. It describes resource discovery the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. traffic Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers parameters to the delivery of metro data services. With a changing mix of transport technologies, the book attributes then examines current and emerging trends, and delves into the role of virtual private networks trunks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic attributes/operations engineering, and MPLS and Generalized MPLS (GMPLS). comparing to LSPs
traffic engineering (TE) 2nd equal-cost multipath IGP metrics MPLS 2nd routing forwarding loop-free

techniques 2nd VC overlays translation VLAN Transparent LAN Service (TLS) transport Ethernet 2nd transport overhead (TOH)

• •

transport overload (TOH) transport services Metro Ethernet EOS 2nd By Sam Halabi troublehsooting congetsion

Table of Contents Index

troubleshooting 2nd Press Publisher: Cisco fault Pubmanagement Date: October 01, 2003 LCAS ISBN: 1-58705-096-X MPLS L3VPN Pages: 240 networks 2nd Notify messages trunking 2nd trunks RSVP-TE 2nd

The definitive guide to Enterprise and Carrier Metro Ethernet applications. traffic
attributes/operations comparing to LSPs tunnels aggregation bypass GRE LSPs

Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts experience of industry innovator and best-selling Cisco Press author, Sam of Internet Routing Architectures

hierarchies 2ndthe Gain from MPLS fast reroute 2nd Halabi, author PSN

RSVP networks LSP 2nd Metro will emerge as the next area of growth for the networking industry and will type length value (TLV) shift in how data services are offered to businesses and residential customers. represent a major type value (TLV) fields been a challenging environment for delivering data services because it has The length metro has always types been built to handle the stringent reliability and availability needs for voice. Carriers will have to protection golink through fundamental shifts to equip the metro for next-generation data services demanded encoding customers and consumers. This is not only a technology shift, but also a shift in the byLSP enterprise of PW operational and business model that will allow the incumbent carriers to transform the metro to of service providers offer enhanced data services. of VC switching Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services.

Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] U.S. incumbent landscape 2nd 3rd UNI (User-to-Network Interface) 2nd unicast frames unnumbered links unqualified learning untagged Ethernet packets 2nd • Table of Contents User-to-Network Interface (UNI) 2nd • Index Metro Ethernet BySam Halabi

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] values TLV fields variations of deployment VC types VC • (virtual circuit) Table of Contents • support Index VCAT concatenation) 2nd Metro(virtual Ethernet VCI (virtual connection identifier) BySam Halabi VCs overlays Publisher: Cisco Press virtual circuit (VC) Pub Date: October 01, 2003 support virtual concatenation ISBN: 1-58705-096-X [See also concatenation] virtual concatenation Pages: 240 (VCAT) 2nd virtual connection identifier (VCI) virtual path identifier (VPI) Virtual Private LAN (VPLS) 2nd virtual router forwarding (VRF) VLAN

The definitive guide to Enterprise and Carrier Metro Ethernet applications.
switching 2nd tagging 2nd 3rd VLAN Tag Preservation Discover the VLAN Tag Translation or Swapping what they can do for your VPI (virtual path identifier) VPLS (Virtual Private Learn fromLAN) the 2nd easy-to-read VPN

latest developments in metro networking, Ethernet, and MPLS services and organization format that enables networking professionals of all levels to

understand the concepts experience of industry innovator and best-selling Cisco Press author, Sam author of Internet Routing Architectures

components 2nd L2VPN Gain services from 2nd the L3VPNs Halabi,

delivering over IP 2nd

Metro networks will emerge as the next area of growth for the networking industry and will of origin represent a major shift in how data services are offered to businesses and residential customers. target The metro has always been a challenging environment for delivering data services because it has VPN-IPv4 addresses been built to handle the stringent reliability and availability needs for voice. Carriers will have to VPNs goFrame through Relay fundamental shifts to equip the metro for next-generation data services demanded by enterprise VRF (virtual routercustomers forwarding) and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] WAN labels waveband switching wavelength division multiplexing (WDM) WDM

• label switching Table of Contents
WDM (wavelength division multiplexing) • Index WF (Wildcard Filter) 2nd Metro Ethernet wholesale models BySam Halabi Wildcard Filter [See WF] wrapping, ring Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).

[A] [B] [C ] [D] [E] [F] [G] [H] [I ] [J] [L] [M] [N] [O ] [P ] [Q ] [R ] [S] [T] [U] [V] [W] [X] XC (cross-connect)

• •
Metro Ethernet BySam Halabi

Table of Contents Index

Publisher: Cisco Press Pub Date: October 01, 2003 ISBN: 1-58705-096-X Pages: 240

The definitive guide to Enterprise and Carrier Metro Ethernet applications. Discover the latest developments in metro networking, Ethernet, and MPLS services and what they can do for your organization Learn from the easy-to-read format that enables networking professionals of all levels to understand the concepts Gain from the experience of industry innovator and best-selling Cisco Press author, Sam Halabi, author of Internet Routing Architectures Metro networks will emerge as the next area of growth for the networking industry and will represent a major shift in how data services are offered to businesses and residential customers. The metro has always been a challenging environment for delivering data services because it has been built to handle the stringent reliability and availability needs for voice. Carriers will have to go through fundamental shifts to equip the metro for next-generation data services demanded by enterprise customers and consumers. This is not only a technology shift, but also a shift in the operational and business model that will allow the incumbent carriers to transform the metro to offer enhanced data services. Metro Ethernet from Cisco Press looks at the deployment of metro data services from a holistic view. It describes the current metro, which is based on TDM technology, and discusses the drivers and challenges carriers will face in transforming the metro to address data services. Metro Ethernet discusses the adoption of metro Ethernet services and how that has led carriers to the delivery of metro data services. With a changing mix of transport technologies, the book then examines current and emerging trends, and delves into the role of virtual private networks (VPN), virtual private local area networks (VLAN), virtual private LAN services (VPLS), traffic engineering, and MPLS and Generalized MPLS (GMPLS).